Alan Turing

Alan Turing, the younger child of Julius Mathison Turing and Ethel Sara Stoney, was born in London on 23rd June, 1912. His father worked for the Indian Civil Service in Madras. For a while Ethel Turing lived in St Leonards-on-Sea with her two sons. His brother, John, had been born in 1908. (1)

Alan's mother claimed that "Alan was interested in figures - not with any mathematical association - before he could read and would study the numbers on lamp posts, etc." (2) However, he seems to have had difficulty with other skills. He later recalled that he had difficulty grasping the principle of the calendar and as a small child he was "quite unable to predict when Christmas would fall. I didn't even realize that it came at regular intervals." (3)

In 1918 Alan went to St Michael's Primary School in Hastings. When he left three years later the headmistress said: "I have had clever boys and hard-working boys, but Alan is a genius." (4) When he was ten years old he was sent to the Hazel Hurst Preparatory School. Over the next four years he developed a passion for mathematics and science. Sara Turing explained that "as a child he always sought to know underlying principles, and apply them... having at school learnt how to find the square root of a given number, he deduced for himself how to find the cube root." (5)

Julius Mathison Turing retired from the Indian Civil Service in 1924. To avoid heavy taxation on his pension he did not return to England and along with his wife settled in France. "By then, though, Alan was used to his parents being some way away. He even took himself to school by taxi, tipping the porter and the driver. His clear aptitude for science and mathematics did not stand him in good stead in a school that specialized in teaching Latin, Greek, literature and the classics in preparation for public school. Turing's spelling and grammar were poor - and remained so throughout his life." (6)

In 1926 Turing became a student at Sherborne School. The start of the first term coincided with the General Strike and as a result the railway system was not working. Turing was so determined to attend the first day that he cycled 100 km unaccompanied from Southampton to Sherborne. "By the end of his first year at the school he had gained a reputation as a shy, awkward boy whose only skills were in the area of science." (7) His housemaster complained that he started the term with a good grasp of mathematics but by the end of the year was not very good: "He spends a great deal of time in investigations in advanced mathematics to the neglect of his elementary work." (8)

John Turing, Alan's brother, later claimed that the family were well aware of his strange behaviour: "My father, on the whole, either ignored my brother’s eccentricities, or viewed them with amused tolerance but there were deep dudgeons when Alan started to accumulate appalling school reports at Sherborne... The only person in the household who was forever exasperated with Alan, constantly nagging him about his dirty habits, his slovenliness, his clothes and his offhand manners (and much else, most of it with good reason) was my mother. If this was due to some early recognition of his genius, she was certainly doing nothing to foster it by trying to press him into a conventional mould. Needless to say, she achieved nothing by it except a dogged determination on Alan’s part to remain as unconventional as possible." (9) Ben Macintyre has argued that Alan Turing was "probably on the Asperger's spectrum." (10)

At Sherborne School, Alan only had two hours a week of science lessons. The headmaster soon reported to his parents: "If he is to be solely a scientific specialist, he is wasting his time at a Public School". (11) According to Nigel Cawthorne, the headmaster told him that: "It is only the shallowest of minds that can suppose... scientific discovery brings us appreciably nearer the solution of the riddles of the universe." He considered Alan "anti-social" and said that he was "the kind of boy who is bound to be a problem in any kind of school". (12)

One of his friends, Victor Beuttell, was the son of the inventor, Alfred Beuttell. On a visit to the Beuttell family home, he began talking to Alfred about his work on his new invention, the K-ray Lighting System. As David Leavitt, the author of The Man Who Knew Too Much (2006), has pointed out: "When he asked Turing to help him fins a formula for determining what should be the proper curvature of the glass used, the boy not only came up with one immediately but pointed out that the thickness of the glass would also affect the illumination - something no one else had noticed. Beuttell gratefully made the necessary changed, and the lighting system was soon put into production." (13)

Turing came into conflict with his English and Latin teacher, A.H. Trelawney Ross who believed that Germany had lost the First World War because it thought "science and materialism were stronger than religious thought and observance." He added that "as democracy advances, manners and morals recede". Ross was furious when he caught Turing doing algebra during a study period set aside for religious instruction. He was so angry he arranged for Turing to fail both subjects. (14)

Alan Turing developed a close relationship with Christopher Morcom, a fellow student at the school. "Together they discussed the latest scientific news and conducted their own experiments. The relationship fired Turing's intellectual curiosity, but more importantly, it also had a profound emotional effect on him." (15) Turing later recalled: "During the term Chris and I began setting one another our pet problems and discussing our pet methods" and confessed that he "worshipped the ground he trod on." (16) When Alan was sixteen, "the maths master told my mother that there was nothing more that he could teach him and he would have to progress from there on his own." (17)

Alan Turing relationship with Morcom came to an end on 13th February 1930, when his friend died of tuberculosis. Turing wrote to his mother: "I feel that I shall meet Morcom again somewhere and that there will be some work for us to do together as there was for us to do here... It never seems to have occurred to me to make other friends besides Morcom, he made everyone else seem so ordinary." (18)

It has argued that Turing was devastated by the loss of the only person he would ever truly love. "His way of coming to terms with Morcom's death was to focus on his scientific studies in an attempt to fulfill his friend's potential. Morcom, who appeared to be the more gifted of the two boys, had already won a scholarship to Cambridge University. Turing believed it was his duty also to win a place at Cambridge, and then to make the discoveries his friend would otherwise have made." (19)

In 1931 Alan Turing began his studies at King's College. While at Cambridge University he became interested in politics and became a regular reader of the New Statesman. (20) He also became a follower of John Maynard Keynes and became involved in the peace-movement. (21) He joined the Anti-War Council, the purpose of which was to organize chemicals and munitions workers to strike if war was declared.

Turing enjoyed his time at Cambridge and in addition to his academic success "he found himself in a tolerant and supportive environment... homosexuality was largely accepted within the university, which meant that he was free to engage in a series of relationships without having to worry about who might find out, and what others might say." (22) He had brief sexual relationships with several men including James Atkins and Fred Clayton: "It was with Atkins that he had the extended, on-andoff sexual relationship, about which he had ambivalent feelings, because Atkins, in his mind, could not compare with the lost Christopher." (23)

In 1934 Turing attended a lecture given by Max Newman where he explained the work of German mathematician, David Hilbert. As Newman later pointed out: "The Hilbert decision-programme of the 1920's and 30's had for its objective the discovery of a general process, applicable to any mathematical theorem expressed in fully symbolitical form, for deciding the truth or falsehood of the theorem... Many were convinced that no such process was possible, but Turing set out to demonstrate the impossibility rigorously." (24)

Turing published his paper in April 1936. As Nigel Cawthorne pointed out: "What he produced was remarkable... When Newman, in his lecture, described Hilbert's 'definite method' as a 'mechanical process', he started an idea in Turing's head the future repercussions of which would be immense. The word 'mechanical' it its original sense, had referred to manual occupation, to work performed by human beings. By the 1930s, however, mechanical meant gears, rotors, vacuum tubes. It meant a machine. Turing took both definitions to heart." (25)

Alan Hodges has argued that "it is characteristic of Turing that he refreshed Hilbert's question by casting it in terms not of proofs, but of computing numbers. The reformulation staked a clearer claim to have found an idea central to mathematics." (26) To speak of a hypothetical "computing machine" at the time was to break the rules of a fairly rigid orthodoxy. "No such machines existed at the time, only calculating devices too crude to undertake any complex mathematics, and certainly not programmable." (27)

In September 1936 Alan Turing went to study under Alonzo Church at Princeton University. Over the next few months he developed the notion of a "universal computing machine" that could theoretically be programmed to solve any problem capable of solution by a specially designed machine. This concept, now called the Turing Machine, foreshadowed the digital computer. He also studied cryptology and also built three of four stages of an electro-mechanical binary multiplier. Turing studied under Albert Einstein and was offered the post as personal assistant to Professor John von Neumann, the man behind the first American computer. However, after obtaining his PhD in June 1938, he returned to Cambridge University. (28)

In June 1938, Sir Stewart Menzies, the chief of MI6, received a message that the Polish Intelligence Service had encountered a man who had worked as a mathematician and engineer at the factory in Berlin where the Germans were producing the Enigma Machine. The man, Richard Lewinski (not his real name), was a Polish Jew who had been expelled from Nazi Germany because of his religion. He offered to sell his knowledge of the machine in exchange for £10,000, a British passport and a French resident permit. Lewinski claimed that he knew enough about Enigma to build a replica, and to draw diagrams of the heart of the machine - the complicated wiring system in each of its rotors.

Menzies suspected that Lewinski was a German agent who wanted to "lure the small British cryptographic bureau down a blind alley while the Germans conducted their business free from surveillance". Menzies suggested that Alfred Dilwyn Knox, a senior figure at the Government Code and Cypher School, should go to interview Lewinski. He asked Alan Turing to go with him. They were soon convinced that he had a deep knowledge of the machine and he was taken to France to work on producing a model of the machine.

According to Anthony Cave Brown, the author of Bodyguard of Lies (1976): "Lewinski worked in an apartment on the Left Bank, and the machine he created was a joy of imitative engineering. It was about 24 inches square and 18 inches high, and was enclosed in a wooden box. It was connected to two electric typewriters, and to transform a plain-language signal into a cipher text, all the operator had to do was consult the book of keys, select the key for the time of the day, the day of the month, and the month of the quarter, plug in accordingly, and type the signal out on the left-hand typewriter. Electrical impulses entered the complex wiring of each of the rotors of the machine, the message was enciphered and then transmitted to the right-hand typewriter. When the enciphered text reached its destination, an operator set the keys of a similar apparatus according to an advisory contained in the message, typed the enciphered signal out on the left-hand machine, and the right hand machine duly delivered the plain text. Until the arrival of the machine cipher system, enciphering was done slowly and carefully by human hand. Now Enigma, as Knox and Turing discovered, could produce an almost infinite number of different cipher alphabets merely by changing the keying procedure. It was, or so it seemed, the ultimate secret writing machine." (29) Mavis Batey, who worked at the Government Code and Cypher School, pointed out the "Polish replica moved the breaking of Enigma on from a theoretical exercise to a practical one and Knox always gave the Poles credit for the part they played." (30)

On the outbreak of the Second World War the Government Code and Cypher School was established at Bletchley Park. Bletchley was selected simply as being more or less equidistant from Oxford University and Cambridge University since the Foreign Office believed that university staff made the best cryptographers. The house itself was a large Victorian Tudor-Gothic mansion, whose ample grounds sloped down to the railway station. Lodgings had to be found for the cryptographers in the town. Some of the key figures in the organization, including its leader, Alfred Dilwyn Knox, always slept in the office. (31)

Alan Turing, considered to be the country's most talented young mathematician, was one of the first people recruited to work at the Government Code and Cypher School in September 1939. A fellow codebreaker, Peter Hilton commented: "Alan Turing was unique. What you realise when you get to know a genius well is that there is all the difference between a very intelligent person and genius. With very intelligent people, you talk to them, they come out with an idea, and you say to yourself, if not to them, I could have had that idea. You never had that feeling with Turing at all. He constantly surprised you with the originality of his thinking. It was marvellous." (32)

By 1939 radio communication was a vital aspect of modern warfare. Radio was used for aerial, naval and mobile land warfare. However, it was very important that the enemy was not aware of these messages. Therefore all radio communications had to be disguised. The main task of the codebreakers was to read messages being sent by the German Enigma Machine. The situation was explained by Francis Harry Hinsley: "By 1937 it was established that... the German Army, the German Navy and probably the Air Force, together with other state organisations like the railways and the SS used, for all except their tactical communications, different versions of the same cypher system - the Enigma machine which had been put on the market in the 1920s but which the Germans had rendered more secure by progressive modifications." (33)

By studying old decrypted messages, Turing discovered that many of them conformed to a rigid structure. He found that he could sometimes predict part of the contents of an undecyphered message, based on when it was sent and its source. As Simon Singh has explained: "For example, experience showed that the Germans sent a regular enciphered weather report shortly after 6 a.m. each day. So, an encrypted message intercepted at 6.05 a.m. would be almost certain to contain wetter, the German word for 'weather'. The rigorous protocol used by any military organization meant that such messages were highly regimented in style, so Turing could even be confident about the location of wetter within the encrypted message. For example, experience might tell him that the first six letters of a particular cypher text corresponded to the plaintext letters wetter. When a piece of plaintext can be associated with a piece of cypher text, this combination is known as a crib. Turing was sure that he could exploit the cribs to crack Enigma." (34)

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The problem for Turing and the rest of the team was that at the time they had to use a "trial and error" approach. This was a very difficult task as there were 159,000,000,000,000,000,000 possible settings to check. R. V. Jones was one of those who worked with Alan Turing on this project: "Together we worked out ways in which the process might be done mechanically, with a machine that would recognize when genuine German was coming out by the frequencies with which various letters and diphthongs appeared." (35)

Another member of the team at Bletchley Park, Peter Calvocoressi, explained the task that faced the codebreakers. "Although its keyboard was simpler than a typewriter's, the Enigma machine was in all other respects much more complicated. Behind the keyboard the alphabet was repeated in another three rows and in the same order, but this time the letters were not on keys but in small round glass discs which were set in a flat rectangular plate and could light up one at a time. When the operator struck a key one of these letters lit up. But it was never the same letter. By striking P the operator might, for example, cause L to appear; and next time he struck P he would get neither P nor L but something entirely different. This operator called out the letters as they appeared in lights and a second operator sitting alongside him noted them down. This sequence was then transmitted by wireless in the usual Morse code and was picked up by whoever was supposed to be listening for it."

Both the person sending and receiving the message had a handbook that told him what he had to do each day. This included the settings of the machine. As Calvocoressi pointed out: "These parts or gadgets consisted of a set of wheels rotors and a set of plugs. Their purpose was not simply to turn P into L but to do so in so complex a manner that it was virtually impossible for an eavesdropper to find out what had gone on inside the machine in each case. It is quite easy to construct a machine that will always turn P into L, but it is then comparatively easy to find out that L always means P; a simple substitution of this kind is inadequate for specially secret traffic. The eavesdropper's basic task was to set his machine in exactly the same way as the legitimate recipient of the message had set his, since the eavesdropper would then be able to read the message with no more difficulty than the legitimate recipient. The more complex the machine and its internal workings, the more difficult and more time-consuming was it for the eavesdropper to solve this problem.... Although only three wheels could be inserted into the machine at any one time, there were by 1939 five wheels issued with each machine. The operator had to use three of this set of five. He had to select the correct three and then place them in a prescribed order. This was crucial because the wheels, although outwardly identical, were differently wired inside." (36)

In 1939 Alan Turing had a meeting with Marian Rejewski, a mathematician who had been working for the Polish Cypher Bureau. He had been trying for seven years to understand the workings of the Enigma machine. When the country was invaded by the German Army, Rejewski managed to escape to France. He told Turing that he had come to the conclusion that as the code had been generated by a machine it could be broken by a machine. In Poland he had built a machine that he named "bomba kryptologiczna" or "cryptological bomb". This machine took over 24 hours to translate a German message on an Enigma machine. Turing was impressed by what Rejewski had achieved but realised that they must find a way of achieving this in a shorter time period if this breakthrough was to be effective. (37)

Alan Turing set about developing an engine that would increase the speed of the checking process. Turing finalized the design at the beginning of 1940, and the job of construction was given to the British Tabulating Machinery factory at Letchworth. The engine (called the "Bombe") was in a copper-coloured cabinet. (38) "The result was a huge machine six-and-a-half feet tall, seven feet long and two feet wide. It weighed over a ton, with thirty-six 'scramblers' each emulating an Enigma machine and 108 drums selecting the possible key settings." (39) Its chief engineer, Harold Keen, and a team of twelve men, built it in complete secrecy. Keen later recalled: "There was no other machine like it. It was unique, built especially for this purpose. Neither was it a complex tabulating machine, which was sometimes used in crypt-analysis. What it did was to match the electrical circuits of Enigma. Its secret was in the internal wiring of (Enigma's) rotors, which 'The Bomb' sought to imitate." (40)

To be of practical use, the machine would have to work through an average of half a million rotor positions in hours rather than days, which meant that the logical process would have to be applied to at least twenty positions every second. (41) The first machine, named Victory, was installed at Bletchley Park on 18th March 1940. It was some 300,000 times faster than Rejewski's machine. (42) "Its initial performance was uncertain, and its sound was strange; it made a noise like a battery of knitting needles as it worked to produce the German keys." (43) They were described by operators as being "like great big metal bookcases". (44)

Frederick Winterbotham was the chief of Air Intelligence at MI6. He later described the moment when Major General Sir Stewart Menzies, the chief of MI6, first gave him copies of German secret messages: "It was just as the bitter cold days of that frozen winter were giving way to the first days of April sunshine that the oracle of Bletchley spoke and Menzies handled me four little slips of paper, each with a short Luftwaffe message on them... From the Intelligence point of view they were of little value, except as a small bit of administrative inventory, but to the back-room boys at Bletchley Park and to Menzies... they were like the magic in the pot of gold at the end of the rainbow. The miracle had arrived." (45)

A more improved version, called Agnus Dei (Lamb of God), was delivered on 8th August. From this point onwards, Bletchley Park was able to read, on a daily basis, every single Luftwaffe message - something in the region of one thousand a day. (46) At the time, the Battle of Britain was raging and the German codes were being broken at Bletchley Park, allowing the British to direct their fighters against incoming German bombers. When the battle was won the codebreakers intercepted messages cancelling the planned invasion of Britain - Operation Sea Lion. (47)

By 22nd May, 1940, British Military Intelligence was able, as a result of the efforts of hundreds of codebreakers decrypting the German Air Force Enigma at Bletchley, to read the most secret German Air Force commanders in France. This made it clear that the German priority was the defeat of France. Not a single Enigma message referred to any move of aircraft needed for Adolf Hitler to follow up the Dunkirk success by an assault across the Channel - Operation Sea Lion. (48)

One of the first important messages concerned the Knickebein Radio System being used by German bombers. Jones analysed this message and came to the conclusion that "it looked to me as though Knickebein might be some kind of beamed beacon which that day had been set to transmit in a north-westerly direction." Jones told Frederick Lindemann, the government's chief scientific, that he was convinced that the Germans had a radio beam transmitter called Knickebein set up at Cleves, on the nearest German soil to England and that it was part of an intersecting beam system for bombing England.

Lindemann told Winston Churchill that "there seems some reason to suppose that the Germans have some type of radio device with which they hope to find their targets". Orders were given to interrogate prisoners from the German bombers that had recently been shot down. Most refused to talk but one prisoner who professed to be anti-war admitted that the new bomb-dropping device involved two intersecting radio beams and it had been developed at Rechlin. The prisoner drew a sketch of what he thought was one of the transmitting towers which he had seen. The RAF had been collecting information about any unusual towers that had been seen in Germany. The drawing provided by the prisoner agreed exactly with a tower that had been photographed near an airfield at Hörnum.

Jones was called to a meeting of the War Cabinet: "Churchill asked me what we could do. I told him that the first thing was to confirm their existence by discovering and flying along the beams for ourselves, and that we could develop a variety of counter-measures ranging from putting in a false cross-beam to making the Germans drop their bombs early, or using forms of jamming ranging from crude to subtle... And then the meeting ended. There were no minutes, because the matter seems to have been deemed so secret that no secretaries were present, and the only record was the one that I made for my report written during the following week."

Following further investigations it was discovered that Jones's predictions had been correct: "Our conclusions had been confirmed: there were indeed two beams, whose bearings were consistent with transmitters at Cleves and Bredstedt.... All doubts were now removed, and plans for counter-measures could go urgently ahead." In his final report to Churchill, R. Jones argued: "There are many lessons in this story, most of which are too obvious to point out. It shows the German technique is well-developed - almost beyond what we thought possible." (49)

Greg Goebel, the author of The Battle of the Beams (2013) has pointed out that by September, 1940, the British had found a way of dealing with Knickebein: "The British were operating more powerful anti-Knickebein transmitters that degraded Knickebein signals by injecting them with Morse code patterns. Since the beams were codenamed 'Headaches', the transmitters were named 'Aspirins'. Knickebein had been neutralized. Without direction, German bombers sometimes got lost in the dark, and at least one crashed because the pilot became completely disoriented, losing control of his aircraft and causing his crew to bail out before the bomber slammed into the ground." (50)

In June 1940 Joan Clarke went to work for Alan Turing in Hut 8. Joan later recalled: "I can remember Alan Turing coming in as usual for a day's leave, doing his own mathematical research at night, in the warmth and light of the office, without interrupting the routine of daytime sleep." (51) The two quickly developed a close relationship. He found her intellectually satisfying as she was able to discuss papers he had written. They were also both keen on chess and although Joan had only recently learnt to play, they were quite well matched. "As they only had a cardboard pocket set, and proper pieces were unobtainable in wartime conditions, so they improvised their own solution. Alan got some clay from one of the local pits, and they modelled the figures together. Alan then fired them on the hob of the coal fire in his room at the Crown Inn. The resulting set was quite usuable, if somewhat liable to breaking. He also tried to make a one-valve wireless set, telling her about the one he had made at school, but this was not such a success." (52)

Alan Turing eventually proposed marriage and Joan Clarke gladly accepted. (53) Nigel Cawthorne, the author of The Enigma Man (2014) suggests that "Turing was not much of a catch... Sometimes he appeared in the office in his pyjamas, or wore trousers held up by a striped necktie instead of a belt. His hair was unkempt and he had a permanent five o'clock shadow, refusing to shave with anything but an ancient electric razor. Though he did not smoke, his teeth were yellow and he bit his fingernails. He was also a workaholic." (54)

A few days later he told her that the marriage might have problems as he had "homosexual tendencies." (55) Clarke's biographer, Lynsey Ann Lord, has argued: "To understand her decision to continue with the engagement following his disclosure, it has to be made clear that during this period in history, marriage for many women, was considered a social duty and it was not necessary that marriage should correspond with sexual desires." Alan Hodges agrees and claims that "many people, in 1941, would not have thought it important that marriage did not correspond with his sexual desires; the idea that marriage should include a mutual sexual satisfaction was still a modern one, which had not yet replaced the older idea of marriage as a social duty. One thing that Alan never questioned was the form of the marriage relationship, with the wife as housekeeper." (56)

The engagement was continued and he gave her a ring. Alan also took Joan to Guildford to meet his mother. They also had lunch with her parents, William and Dorothy Clarke. Alan told Joan about some of his homosexual relationships but claimed that this kind of behaviour was over. He even said that he would like them to have children. However, he eventually decided that he could not go through with the marriage and broke the relationship off. (57)

On 6th September, 1941, Prime Minister Winston Churchill and Sir Stewart Menzies, the head of MI6, visited Bletchley Park. Churchill was shocked by the wide variety of backgrounds of the codebreakers: "In addition to the mathematicians and linguists, there was an authority on porcelain, a curator from the Prague Museum, the British chess champion and numerous bridge experts." Churchill told Menzies: "I told you to leave no stone unturned, but I didn't expect you to take me so literally." (58)

Turing believed that Bletchley Park needed more staff to carry out the task of dealing with so many secret German messages. On 21st October 1941, Turing wrote to Churchill: "Some weeks ago you paid us the honour of a visit, and we believe that you regard our work as important. You will have seen that, thanks largely to the energy and foresight of Commander Travis, we have been well supplied with the 'bombes' for the breaking of the German Enigma codes. We think, however, that you ought to know that this work is being held up, and in some cases is not being done at all, principally because we cannot get sufficient staff to deal with it. Our reason for writing to you direct is that for months we have done everything that we possibly can through the normal channels, and that we despair of any early improvement without your intervention." (59)

Churchill told his principal staff officer: "Make sure they have all they want on extreme priority and report to me that this has been done." By the end of 1942 there were 49 Turing machines. As part of the recruitment drive, the Government Code and Cypher School placed a letter in the Daily Telegraph. They issued an anonymous challenge to its readers, asking if anybody could solve the newspaper's crossword in under 12 minutes. It was felt that crossword experts might also be good codebreakers. The 25 readers who replied were invited to the newspaper office to sit a crossword test. The six people who finished the crossword first were interviewed by military intelligence and recruited as codebreakers at Bletchley Park. (60)

After the death of his boss, Alfred Dilwyn Knox, in February, 1943, Turing became the chief consultant to the vast cryptanalytic operation. By this time Ultra had become a major industry and employed some 6,000 people to translate over 2,000 messages a day. However, Turing was suffering from stress: "Turing was a man of enormous intellect but, by then, few reserves of nervous energy. He was nearing the end of his tether as he coaxed his battery of engines at Bletchley to penetrate Enigma-enciphered U-boat communications and pinpoint the movements of his fearful enemy." (61)

Alan Turing behaviour became more eccentric. "He would convert the family money into silver ingots at the outbreak of war, bury them, and then forget where they were. He corresponded with friends in a cipher punched onto a tape which no one could read. He was a talented long-distance runner and would on occasion arrive at conferences at the Foreign Office in London having run the 40 miles from Bletchley in old flannels and a vest with an alarm clock tied with binder twine around his waist." (62) His friend, Geoffrey Jefferson, described his "long, disturbing silences punctuated by a cackle" that "wracked the nerves of his closest friends." He added that he was "so unversed in worldly ways, so child-like, so non-conformist, so very absent-minded... a sort of scientific Shelley." (63)

However, his brother, John Turing, believes some of these stories were exaggerated. He was especially critical of Ronald Lewin, the author of Ultra Goes To War (1978) who said that "in some fit of despondency Alan converted all his money into cash and buried it in the Bletchley woods as a reserve against disaster." John Turing claims that: "In fact, he did nothing of the kind. He had decided that if there were a German invasion, banking accounts would be useless, so he bought some silver ingots for use on the black market. These he trundled in an ancient perambulator and buried in a field (not at Bletchley), where he made a sketch map of their position so he could find them after the war. After the war, he enlisted the help of his friend, Donald Michie (now Professor Michie of Edinburgh University), to dig up these ingots - using, typically, a homemade metal detector - but the heavy ingots were by now well on their way to Australia and were never seen again." (64)

According to his biographer, Alan Hodges, Turing became very interested in electronics during the later stages of the war: "Electronics... made its first appearance at Bletchley as telephone engineers were pressed into an effort to enable the machines to work at ever higher speeds, and thus Turing was introduced to the potential of this new and untried technology. He himself devoted much time to learning electronics, ostensibly for his own, elegant, speech secrecy system, effected with one assistant, Donald Bayley, at nearby Hanslope Park. However, he had a more ambitious end in view: in the last stage of the war (for his part in which he was appointed OBE), he planned the embodiment of the universal Turing machine in electronic form, or, in effect, invented the digital computer.... In 1944 Turing knew his own concept of the universal machine; the speed and reliability of electronics; and the inefficiency of building new machines for new logical processes. These provided the principle, the means, and the motivation for the modern computer, a single machine capable of any programmed task. He was spurred by a fourth idea that the universal machine should be able to acquire the faculties of the brain."

It has been claimed that Turing's work enabled much of modern technology to take place: "Turing was captivated by the potential of the computer he had conceived. His earlier work had shown the absolute limitations on what any Turing machine could do, but his fascination now lay in seeing how much such machines could do, rather than in what they could not, and in the power of the concept of the universal machine. Indeed from now on he argued that uncomputable functions were irrelevant to the problem of understanding the action of the mind. His thought became strongly determinist and atheistic in character, holding that the computer would offer unlimited scope for practical progress towards embodying intelligence in an artificial form." (65)

After the war Alan Turing lived in Richmond while he worked on the design of the ACE (Automatic Computing Engine) at the National Physical Laboratory (NPL). In 1947 he returned to Cambridge University and produced an unpublished paper on Intelligent Machinery. In 1948, he was appointed Reader in the Mathematics Department at the University of Manchester. The following year he became Deputy Director of the university's Computing Laboratory and produced software for one of the earliest stored-program computers. (66)

In 1950 he addressed the problem of artificial intelligence. He developed what became known as the Turing Test. He stated that with a person in one room and the machine in another, an interrogator in a third room asks questions of both to try to identify them. When the interrogator cannot distinguish between them by questioning, the machine will have reached a state of human-like intelligence.

In December 1951 Alan Turing met Arnold Murray, a 19-year-old unemployed man while walking the streets of Manchester. "Alan invited him to lunch in the restaurant across the road. Fair and with blue eyes, undernourished and with his thin hair already receding, desperate for better things and more receptive than so many educated people, Arnold touched Alan's soft spot for lost lambs, as well as other cords." Turing told him about his work and Arnold pleased him by asking sensible questions about his research. (67)

They agreed to meet again and on 12th January 1952, Arnold visited Alan's home in Wilmslow. Two days later he spent the night with Alan. Not wanting to be treated as a prostitute, "Arnold rebuffed Turing's efforts to give him cash." The following day he noticed that £10 was missing from his wallet. When he saw him later that week he accused Arnold of stealing his money. He denied it but admitted he was in debt and asked for a loan of £3. On 18th January Arnold asked him for another £7. (68)

On 23rd January he arrived home to find his house burgled. He wrote to his friend, Fred Clayton: "I have just had my house broken into, and am still every few hours finding some fresh thing missing. Fortunately I am insured, and little has gone that is really irreplaceable. But the whole thing has had a very disturbing effect, especially as it followed shortly on a theft from me at the University." (69)

Alan Turing reported the burglary to the police and two CID officers came to take fingerprints in the house. On 2nd February, Arnold returned to Alan's house. After having a few drinks together Arnold admitted that a friend of his, Harry, a twenty-year old unemployed man, was responsible for the burglary. The following morning Alan reported this information to the police. Harry was in custody on another charge and they had already matched his fingerprints with those found in Alan's house. The CID officers began to ask him about his relationship with Arnold. He confessed to having a homosexual relationship with Arnold and then wrote a five page statement giving full details of what had taken place between the two men. Alan added that he was convinced that Parliament was just about "to legalize it". Arnold was now arrested and both men were charged with gross indecency under Section 11 of the Criminal Law Amendment Act 1885. (70)

Turing wrote to Joan Clarke, who was now engaged to be married to Lieutenant-Colonel J. K R Murray. (71) He admitted that he had been having sex with other men and that "he had been found out". He tried to assure her that he would not be sent to prison and claimed that "they're not as savage as they used to be". He had been told that only 174 of the 746 men prosecuted for gross indecency had been imprisoned, and then mostly for less than six months. He was also a "first offender" which diminished the chances of imprisonment. (72)

Turing and Murray went on trial on 31st March 1952. Max Newman and Hugh Alexander both appeared as character witnesses. Turing and Murray were found guilty. Murray was given a conditional discharge. Turing was placed on probation, which would be conditional on his agreement to undergo hormonal treatment designed to reduce his sex drive. He accepted the option of treatment via injections of stilboestrol, a synthetic oestrogen; this treatment was continued for the course of one year. Turing wrote to his friend, Philip Hall: "I am both bound over for a year and obliged to take this organo-therapy for the same period. It is supposed to reduce sexual urge whilst it goes on... The psychiatrists seemed to think it useless to try and do any psychotherapy." (73) The treatment rendered Turing impotent.

Turing's conviction led to the removal of his security clearance and barred him from continuing with his cryptographic consultancy for the Government Communications Headquarters (GCHQ). The case of the two Soviet spies, Guy Burgess and Donald Maclean, who were both homosexuals, convinced the authorities that Turing was a security risk and was forbidden to work on research projects relating to the development of the computer. (74) He was also denied entry into the United States.

At his home in Wilmslow he began making certain chemicals, among them potassium cyanide. On 7th June, 1954, he coated an apple with some of the cyanide, went to bed and bit the apple and died. The coroner pronounced at the inquest: "I am forced to the conclusion that this was a deliberate action, for with a man of this type one can never be sure what his mental processes are going to do next. Here was a brilliant mathematician with unusual mental achievements. he might easily become unbalanced and unstable." (75)

My brother Alan was born on 21st June 1912 in a London nursing home. At this, and at all other times, my father took all decisions of consequence in the family. Now, rightly or wrongly, he decided that he and my mother should return alone to India, leaving both children with foster parents in England. Alan and I were left with “the Wards” - always we referred to them as “the Wards.” We were the wards and they were our guardians but no matter - this was to be the centre of our existence for many years and our home from home. I believe it was here, perhaps in the first four or five years at the Wards, perhaps even in the first two, that Alan became destined for a homosexual. Has anyone mentioned it until now?

No. My mother was fully aware of it before Alan’s death (not, I imagine, that she had the faintest idea of what it implied), but she makes no reference to it in her book. One can put that down to Edwardian reticence if one pleases. In my view, based on such conversation as I had with my mother about it, necessarily reduced to a minimum, her reaction was much what one might expect if a specialist had informed her that her son was color blind or had an incurable obsession with spiders: it was a nasty shock of brief duration and of no great significance. I am trying to make this memoir as truthful as I can, so I will not go to the length of pretending that I like homosexuals. To my mind, what is intolerable is the world of the “gay crusade” and, as my unfortunate brother may be cast in the part of an early and valiant crusader, this is by no means an irrelevant comment.

My mother, perhaps unwittingly, gives the impression in her book that she recognized Alan’s genius from the start, and that she sedulously fostered it. If so, she did not give that impression in the family at the time; in fact, quite the contrary.

My father, on the whole, either ignored my brother’s eccentricities, or viewed them with amused tolerance but (as will appear) there were deep dudgeons when Alan started to accumulate appalling school reports at Sherborne. As for myself, with the selfishness of youth, and separated by a gap of four years, I did not care what Alan did, and I was content to go my own way, as indeed he was content to go his. Our interests were so dissimilar that they never clashed. Needless to say, she achieved nothing by it except a dogged determination on Alan’s part to remain as unconventional as possible. The truth of the matter, as I now view it in retrospect, is that neither of Alan’s parents or his brother had the faintest idea that this tiresome, eccentric and obstinate small boy was a budding genius. The business burst upon us soon after he went to Sherborne. After a few terms, it became apparent that he was far ahead of the other boys in mathematics: when Alan was sixteen, the maths master told my mother that there was nothing more that he could teach him and he would have to progress from there on his own. I think it must have been when Alan was due to take the School Certificate examination (now replaced by “O” levels) that he read Hamlet in the holidays. My father was delighted when Alan placed the volume on the floor and remarked “Well, there’s one line I like in this play.” My father could already see a burgeoning interest in English literature. But his hopes were dashed when Alan replied that he was referring to the final stage direction (Exeunt, bearing off the bodies).

Alan was first class at beating the system. He refused to work at anything except his precious maths and science, but he had an incredible aptitude for examinations, aided by last minute swotting. At Sherborne, marks were awarded both for term’s work and examination results; these were read out in turn, followed by the combined result. On one famous occasion, he was twenty-second out of twenty-three on the term’s work, first in exams and third on the combined results. One Easter holiday in Dinard, he spent all his time collecting seaweed and brewing it up in the cellar until at length he extracted a few drops of iodine which he carried back to the science master at Sherborne in high triumph. When later we were living in Guildford, he had a series of crazes. He tried to learn the violin, which was excruciating. Then he turned his attention to breeding those little red banana flies in test tubes, so that he could prove Mendel’s theory at first hand. Unfortunately, they escaped and the house was full of banana flies for several days. Oddest of all, in the heat of summer, he spent much of his time dressed as a private soldier allegedly drilling at Knightsbridge barracks, to what purpose nobody knew, but looking back on it now, I strongly suspect that drilling was not the object of the exercise at all. He was, as I have said, good at beating the system and, of course, the odder the things he did, the less one was likely to enquire into them.

In 1931, Alan went to King’s College, Cambridge, with a mathematical scholarship. Soon afterwards, in March 1935, he wrote the thesis for which he was awarded a Fellowship, at the unusually early age of twenty-two. I have a horrid recollection of “The Gaussian Error Function” (whatever that might be), for Alan had left it to the eleventh hour to sort the sheets, parcel and dispatch them. My mother and I spent a frantic half hour on hands and knees putting them in order; Mother did up the parcel in record time and Alan sped with it to the GPO3 on his bike, announcing on his return that there were at least twenty minutes to spare. This is my only positive contribution to mathematical thought.

On or before the outbreak of war, Alan was recruited from King’s College, Cambridge, along with other promising mathematicians, To work as a code-breaker at Bletchley. Much has been written about this establishment in recent years, including a great deal of rubbish about Alan; one author, who shall remain nameless, describing him as the son of his maternal grandfather. Of course, none of us knew then, nor for many years after the war, what Alan was doing at Bletchley, where he spent most of the early part of the war. In fact, he was engaged in breaking the German naval codes. The best and shortest book on the work at Bletchley is Peter Calvocoressi’s Top Secret Ultra, published by Cassell, As someone rightly remarked, for thus saving the nation from disaster, Alan should have been given an earldom but, in fact, he was awarded an OBE, which, to the amusement of his friends, but quite properly, in my opinion, he kept in a tin box along with such aids to gracious living as screws, nails, nuts and bolts.

My brother’s eccentricities have become legendary and some of them have become distorted in the process. For example, Mr. Ronald Lewin, in his book, Ultra Goes To War, says that “… in some fit of despondency Alan converted all his money into cash and buried it in the Bletchley woods as a reserve against disaster.” In fact, he did nothing of the kind. After the war, he enlisted the help of his friend, Donald Michie (now Professor Michie of Edinburgh University), to dig up these ingots - using, typically, a homemade metal detector - but the heavy ingots were by now well on their way to Australia and were never seen again.

I hope the author of the book recommended by Mr. Watkins will be sufficiently acute to distinguish eccentricity from idiosyncracy and both from the just plumb crazy. I rather think that my brother ran the whole gamut. In the “just plumb crazy” class, I put the business of his chaining his mug to the radiator to prevent its being stolen. This may, however, have been one of his practical jokes because he was heard to declare that he had devised a special code for the lock which he defied the other cryptographers to decipher. If the episode of “the burglar” had not proved, ultimately, so fatal to Alan, I suppose this, too, might have been regarded as farcical. It occurred a couple of years before Alan’s death and I believe that it was this that turned the scales against him. I had never had even the faintest notion that Alan was a homosexual. One did not in those days (at least in our middle class) talk or even think about homosexuals and lesbians: one had heard of them, of course. (There was a book called Pansies by D.H. Lawrence, displayed in Hatchards bookshop in Piccadilly when I was an articled clerk aged about 21. “Another boring gardening book,” I sighed as I passed by.) I expect we were a little stupid.

One morning, there arrived a letter for me from Alan - a remarkable thing of itself, neither a postcard nor a telegram. I opened it and the first sentence read “I suppose you know I am a homosexual.” I knew no such thing. I stuffed the letter in my pocket and read it in the office. There followed the story of “the burglar.” He was not a burglar, not even a housebreaker. At this time, Alan was working at Manchester University. The so-called “burglar” was, in fact, a nasty young man whom Alan had picked up in Manchester (or the other way about) and had come by invitation to Alan’s house. On his way out, he relieved Alan of his gold watch (left to him by his father) and a few other portable items. That was the “burglar” - so then, and for afterwards, described by Alan.

Alan foolishly but typically reported the loss to the police, who did not seem much interested in “the burglar.” But they were greatly interested in the prospect of prosecuting a don, a near-Olympic runner and a Fellow of the Royal Society for homosexual practices, then proscribed by the law. Alan then consulted his University friends, who strongly advised him to defend the case, instruct leading counsel and heaven knows what else. In the meantime, would I kindly inform our mother of the situation? The short answer to that was that I would not.

So I dropped everything and went to Manchester where I consulted Mr. G, the senior partner in a leading firm of Manchester solicitors. He, in turn, saw Alan’s solicitor, Mr. C, who persuaded Alan to plead guilty. In consequence, the case received the minimum of publicity. Alan was put on probation in return for an undertaking that he would undergo medical treatment. He remained secure in his university post and there were no headlines in the national press to alarm my mother. Meanwhile, he had grudgingly consented to visit her upon my insistence that she must be forewarned in case the journalists got hold of it. What exactly he told her or what she understood of it, I don’t know: she did not seem to be greatly interested.

Alan did not seem to understand, even then, how close he had been to disaster, though did he, I wonder, have some premonition of things to come? He continued to talk about “the burglar” and wrote me an unpleasant letter suggesting that I cared nothing for his plight or that of homosexuals in general (the letter, perhaps, being not far wide of the mark) and that I was merely concerned to protect myself and my partners from adverse comment in the City from our Establishment friends. It was so far from the truth that I sent him a tart reply of which I feel ashamed. It was a disagreeable business and the only occasion I can remember that we quarreled.

Some two years later, during the Whitsun holiday, I had taken one of my daughters to the cinema and arrived home about 10.30pm. In my absence, the Manchester police had telephoned to say that Alan had been found dead in his house. Late as it was, I telephoned the ever kindly and shrewd Mr. G, who promised to meet me at the station in Manchester the next morning. He took me to the police and thence we went to the mortuary where I identified Alan’s body. He had taken cyanide. By great good fortune, my mother was on holiday in Italy and did not return home until after the inquest.

Mr G advised me strongly not to instruct counsel to appear at the inquest and told me of the unhappy course which some other cases had taken before this coroner, a retired doctor who could not abide lawyers. The possibility of establishing death by accident was minimal; the best we could hope for was the considerate verdict of “balance of mind disturbed.”He was right and I accepted his advice. At the inquest itself, this soon became apparent: there were present some eight or nine reporters, some from the national press, with pencils poised and waiting for the homosexual revelations. They were disappointed. I gave evidence briefly. The coroner asked me a few perfunctory questions. The verdict was as anticipated. When my mother returned, she was highly indignant and made no secret of her belief that I had grossly mishandled the case. She evolved various theories of her own to establish to her own satisfaction that it was really an accident. But I had worked on the very same theories myself in Manchester for nearly three days and there was one fatal flaw in them. This was the half-eaten apple beside Alan’s bed where his body was found. The apple was to disguise the bitter taste of the cyanide and thus ensure that the poison would do its work.

In those unhappy days in Manchester, I visited Alan’s psychiatrist who told me a great deal about Alan that I did not know before - among other things, that he loathed his mother. I refused to believe it. He then handed me two exercise books in which Alan had entered such matters as psychiatrists require of their patients, including their dreams. “You had better take them away and read them,” he said, adding that there was a third book, probably in Alan’s house. I viewed the two books in my hotel with horror, but I was still bent on proving the accident theory and decided I had better read them. I wish I had not. Alan had been a practicing homosexual since the age of puberty. His comments on his mother were scarifying. To my great relief, I was mentioned only once or twice and not in opprobrious terms. I returned the books to the psychiatrist the following day. There remained the problem of the third book, for it was essential that it should be found so that it would not fall into my mother’s hands. Eventually it was found and returned to the psychiatrist. Two days later, my mother arrived in Manchester and ransacked the house for clues bearing on her preconceived theories. I need hardly add that she remained unaware of the books and of Alan’s feelings about her until the day of her death.

I think I owe it to their memories to put the record straight. Inevitably, it has fallen to my lot to present some less appealing features of Alan’s character and habits. He was a complex man and much loved by many. Had he been better understood when he was young - and if I, among others, had treated him with more consideration - he might be alive today.

By 1937 it was established that, unlike their Japanese and Italian counterparts, the German Army, the German Navy and probably the Air Force, together with other state organisations like the railways and the SS used, for all except their tactical communications, different versions of the same cypher system - the Enigma machine which had been put on the market in the 1920s but which the Germans had rendered more secure by progressive modifications. In 1937 GC and CS broke into the less modified and less secure model of this machine that was being used by the Germans, the Italians and the Spanish nationalist forces. But apart from this the Enigma still resisted attack, and it seemed likely that it would continue to do so.

As the weeks passed, Turing realized that Bletchley was accumulating a vast library of decrypted messages, and he noticed that many of them conformed to a rigid structure. By studying old decrypted messages, he believed he could sometimes predict part of the contents of an undeciphered message, based on when it was sent and its source. For example, experience showed that the Germans sent a regular enciphered weather report shortly after 6 a.m. For example, experience might tell him that the first six letters of a particular ciphertext corresponded to the plaintext letters wetter. When a piece of plaintext can be associated with a piece of ciphertext, this combination is known as a crib.

Turing was one of the pioneers of computer theory, but he had also long been toying with the notion of a "Universal Machine," not a computer, but a machine which, when supplied with suitable instructions, would imitate the behavior of another machine. Or, as Turing explained its function: "A sonnet written by a machine will be better appreciated by another machine."

His friends said that such a machine was an impossibility. It would have to be as large as St. Paul's Cathedral or the Capitol Building; it would require new universities wholly dedicated to the training of high skills to man it; it would need more power than a facility the size of Boulder Dam could produce. But Turing was not dissuaded, and he persisted with his theories. He wrote a number of papers of major importance, among them one that would give him, according to his obituary in The Times, "a permanent place in mathematical logic." Turing never said (outside his own tiny professional circle) how his theories could be applied to cryptanalysis. But as his mother would write in an In Memoriam about her son, "In answer to a question of mine regarding the application of mathematics to mundane ends, Alan referred to something he had been working on, which might be of military value. He gave no details. But as he had some scruples about the application of any such device (to military affairs), he consulted me about its moral aspects."

Yet for all his intelligence, his scruples and his dreams, Turing had a very odd, childlike side to his nature. He listened every night to "Toytown," a children's play about Larry the Lamb on the BBC, keeping the long-distance telephone line open to his mother so that they could discuss each development. While working at Bletchley, he was arrested by an officer of the Buckinghamshire Constabulary who encountered him walking down a country lane with his gas mask on. It filtered pollen, Turing explained, and he suffered from hay fever. He would convert the family money into silver ingots at the outbreak of war, bury them, and then forget where they were. He was a long-distance runner and would on occasion arrive at conferences at the Foreign Office in London having run the 40 miles from Bletchley in old flannels and a vest with an alarm clock tied with binder twine around his waist. He was "wild as to hair, clothes and conventions," and given to "long, disturbing silences punctuated by a cackle" that "wracked the nerves of his closest friends." But of his genius there was no doubt. Sir Geoffrey Jefferson, who would propose his membership to the Royal Society, the most august of scientific bodies, thought Turing "so unversed in worldly ways, so child-like, so non-conformist, so very absent-minded... a sort of scientific Shelley."

Some weeks ago you paid us the honour of a visit, and we believe that you regard our work as important. Our reason for writing to you direct is that for months we have done everything that we possibly can through the normal channels, and that we despair of any early improvement without your intervention.

Turing was certainly unlike anybody the Foreign Office civil servants had ever worked with before. For a start, he was a practising homosexual which made him a security risk. If he was ever caught breaking the law, he was liable to be blackmailed. Whether or not Denniston knew his sexual preferences, some of his colleagues did. Peter Twinn, Turing's assistant, found out one night in London. Returning to their shared hotel room after dinner, Turing asked Twinn whether they should go to bed together. When Twinn said he was not like that, Turing matter of factly made his excuses and got into his own bed alone. Turing was also very eccentric. One of his closest associates suggested that if examined today, he might have been diagnosed to be suffering from a mild form of autism. Perhaps it was Asperger Syndrome, otherwise known as high grade autism, which Isaac Newton is also thought to have had. People with this disorder frequently come up with brilliant ideas which no normal person could have thought of. At the same time, they have no idea how to relate to other people, and cannot understand what other people will think of their behaviour. Asperger Syndrome sufferers are often obsessive about their work, and like to do it alone.

Whether or not Turing had Asperger Syndrome, he certainly had many of its symptoms. He was an isolated loner at work and at play. In 1934, while still an undergraduate studying mathematics at King's College, Cambridge he had "discovered" the so-called Central Limit Theorem, only to be told subsequently that his "discovery" had already been written up twelve years earlier by another mathematician. He had failed to consult the relevant reference books.He admitted that he had only agreed to research Naval Enigma "because no one else was doing anything about it and I could have it to myself".

An inquest will be held to-day on Dr Alan Mathison Turing, reader in the theory of computing at Manchester University, who was found dead in bed at his home in Adlington Road, Wilmslow, on Tuesday morning. He was 41.

Dr Turing was one of the pioneers of the electronic calculating machine in this country. While at Manchester he was one of the scientists responsible for the “mechanical brains” called “Madam” (Manchester Automatic Digital Machine) and “Ace.” Some of the ideas embodied in “Ace” indeed were envisaged by him as early as 1935.

One of his machines, he claimed, had solved in a few weeks a problem in higher mathematics which had been a puzzle since the eighteenth century. With Professor FC Williams, also of Manchester University, he invented two features for the calculating machines which added immensely to their “memory” and range. These were the magnetic drum for storing permanent information and the cathode ray tube for storing information produced in the calculation for use later on. In an article published in Mind in 1951 Dr Turing seemed to come to the conclusion that digital computators would be able to do something akin to “thinking”. He also discussed the possibilities of educating a “child machine”.

Born in June 1912, he was educated at Sherbourne College and later at King’s College, Cambridge, of which, in 1935, he became a Fellow. He served in the Foreign Office during the war and was awarded the OBE in 1946. From 1945 to 1948 he worked in the National Physical Laboratory at Teddington. He was elected a Fellow of the Royal Society in 1951. His hobbies were long-distance running, chess, and gardening. While at Teddington he was a scratch long-distance runner for the Walton Athletic Club.

The Imitation Game jumps around three time periods – Turing’s schooldays in 1928, his cryptographic work at Bletchley Park from 1939-45, and his arrest for gross indecency in Manchester in 1952. It isn’t accurate about any of them, but the least wrong bits are the 1928 ones. Young Turing (played strikingly well by Alex Lawther) is a lonely, awkward boy, whose only friend is a kid called Christopher Morcom. Turing nurtures a youthful passion for Morcom, and is about to declare his love when Morcom mysteriously fails to return after a holiday. Turing is summoned into the headmaster’s office, and is told coldly that the object of his affection has died of bovine tuberculosis. The film is right that this awful event had a formative impact on Turing’s life. In reality, though, Turing had been warned before his friend died that he should prepare for the worst. The housemaster’s speech (to all the boys, not just him) announcing Morcom’s death was kind and comforting.

In the 1939-45 strand of the story, Turing has grown up physically – though not, the film implies, emotionally. He is played by Benedict Cumberbatch, who is always good and puts in a strong performance despite the clunkiness of the screenplay. The film gives him a quasi-romantic foil in cryptanalyst Joan Clarke (Keira Knightley), dubiously fictionalised as the key emotional figure of Turing’s adult life. The real Turing was engaged to her for a while, but he told her upfront that he had homosexual tendencies. According to him, she was “unfazed” by this.

Turing builds an Enigma-code-cracking machine, which he calls Christopher. It’s understandable that films about complicated science usually simplify the facts. This one has sentimentalized them, too: fusing A Beautiful Mind with Frankenstein to portray Turing as the ultimate misunderstood boffin, and the Christopher machine as his beloved creation. In real life, the machine that cracked Enigma was called the Bombe, and the first operating version of it was named Victory. The digital computer Turing invented was known as the Universal Turing Machine. Colossus, the first programmable digital electronic computer, was built at Bletchley Park by engineer Tommy Flowers, incorporating Turing’s ideas.

The Imitation Game puts John Cairncross, a Soviet spy and possible “Fifth Man” of the Cambridge spy ring, on Turing’s cryptography team. Cairncross was at Bletchley Park, but he was in a different unit from Turing. As Turing’s biographer Andrew Hodges, on whose book this film is based, has said, it is “ludicrous” to imagine that two people working separately at Bletchley would even have met. Security was far too tight to allow it. In his own autobiography, Cairncross wrote: “The rigid separation of the different units made contact with other staff members almost impossible, so I never got to know anyone apart from my direct operational colleagues.” In the film, Turing works out that Cairncross is a spy; but Cairncross threatens to expose his sexuality. “If you tell him my secret, I’ll tell him yours,” he says.

The blackmail works. Turing covers up for the spy, for a while at least. This is wholly imaginary and deeply offensive – for concealing a spy would have been an extremely serious matter. Were the makers of The Imitation Game intending to accuse Alan Turing, one of Britain’s greatest war heroes, of cowardice and treason? Creative licence is one thing, but slandering a great man’s reputation – while buying into the nasty 1950s prejudice that gay men automatically constituted a security risk – is quite another....

Historically, The Imitation Game is as much of a garbled mess as a heap of unbroken code. For its appalling suggestion that Alan Turing might have covered up for a Soviet spy, it must be sent straight to the bottom of the class.

Alan Turing - School Student (Answer Commentary)

(1) Alan Hodges, Oxford Dictionary of National Biography (2004-2014)

(2) Sara Turing, Alan M. Turing (1959) page 11

(3) David Leavitt, The Man Who Knew Too Much (2006) page 9

(4) Nigel Cawthorne, The Enigma Man (2014) page 18

(5) Sara Turing, Alan M. Turing (1959) page 15

(6) David Leavitt, The Man Who Knew Too Much (2006) page 21

(7) Simon Singh, The Code Book: The Secret History of Codes & Code-Breaking (2000) page 166

(8) Sara Turing, Alan M. Turing (1959) page 27

(9) John Turing, He Should be Alive Today (22nd June, 2012)

(10) Ben Macintyre, The Real Alan Turing (15th November, 2014)

(11) Alan Hodges, Alan Turing: the Enigma (1983) page 26

(12) Nigel Cawthorne, The Enigma Man (2014) pages 21-22

(13) David Leavitt, The Man Who Knew Too Much (2006) page 15

(14) Nigel Cawthorne, The Enigma Man (2014) page 23

(15) Simon Singh, The Code Book: The Secret History of Codes & Code-Breaking (2000) page 166

(16) Alan Hodges, Oxford Dictionary of National Biography (2004-2014)

(17) John Turing, He Should be Alive Today (22nd June, 2012)

(18) Alan Turing, letter to Sara Turing (16th February, 1930)

(19) Simon Singh, The Code Book: The Secret History of Codes & Code-Breaking (2000) page 166

(20) Nigel Cawthorne, The Enigma Man (2014) page 20

(21) Alan Hodges, Oxford Dictionary of National Biography (2004-2014)

(22) Simon Singh, The Code Book: The Secret History of Codes & Code-Breaking (2000) page 169

(23) Nigel Cawthorne, The Enigma Man (2014) page 20

(24) Max Newman, The Hilbert Decision Programme, included in Mathematical Logic (2001) page 272

(25) Nigel Cawthorne, The Enigma Man (2014) page 54

(26) Alan Hodges, Alan Turing: the Enigma (1983) page 8

(27) Nigel Cawthorne, The Enigma Man (2014) page 58

(28) Mavis Batey, Oxford Dictionary of National Biography (2004-2014)

(29) Anthony Cave Brown, Bodyguard of Lies (1976) page 21

(30) Mavis Batey, Oxford Dictionary of National Biography (2004-2014)

(31) Penelope Fitzgerald, The Knox Brothers (2002) page 228-229

(32) Sinclair McKay, The Secret Life of Bletchley Park (2010) pages 16 and 17

(33) Francis Harry Hinsley, British Intelligence in the Second World War: Volume One (1979-1990) page 53

(34) Simon Singh, The Code Book: The Secret History of Codes & Code-Breaking (2000) page 170

(35) R. Jones, Most Secret War: British Scientific Intelligence 1939-1945 (1978) page 100

(36) Peter Calvocoressi, Top Secret Ultra (1980) pages 34-37

(37) Nigel Cawthorne, The Enigma Man (2014) page 55

(38) Sinclair McKay, The Secret Life of Bletchley Park (2010) page 95

(39) Nigel Cawthorne, The Enigma Man (2014) page 55

(40) Harold Keen, interviewed by Anthony Cave Brown (c. 1970)

(41) Anthony Cave Brown, Bodyguard of Lies (1976) page 23

(42) Nigel Cawthorne, The Enigma Man (2014) page 58

(43) Alan Hodges, Alan Turing: the Enigma (1983) page 231

(44) Mary Stewart, interviewed in the documentary The Men Who Cracked Enigma (2003)

(45) Frederick Winterbotham, The ULTRA Secret (1974) page 15

(46) Sinclair McKay, The Secret Life of Bletchley Park (2010) page 98

(47) Nigel Cawthorne, The Enigma Man (2014) page 58

(48) Martin Gilbert , The Second World War (1989) page 82

(49) R. Jones, Most Secret War: British Scientific Intelligence 1939-1945 (1978) pages 150

(50) Greg Goebel, The Battle of the Beams (1st February, 2013)

(51) Nigel Cawthorne, The Enigma Man (2014) pages 65

(52) Alan Hodges, Alan Turing: the Enigma (1983) pages 260-261

(53) Lynsey Ann Lord, Joan Clarke Murray (2008)

(54) Nigel Cawthorne, The Enigma Man (2014) pages 64-65

(55) Lynsey Ann Lord, Joan Clarke Murray (2008)

(56) Alan Hodges, Alan Turing: the Enigma (1983) page 259

(57) David Leavitt, The Man Who Knew Too Much (2006) page 178

(58) Simon Singh, The Code Book: The Secret History of Codes & Code-Breaking (2000) page 178

(59) Alan Turing, letter to Winston Churchill (21st October, 1941)

(60) Simon Singh, The Code Book: The Secret History of Codes & Code-Breaking (2000) page 181

(61) Anthony Cave Brown, Bodyguard of Lies (1976) page 253

(62) Sara Turing, Alan M. Turing (1959) page 58

(63) Ben Macintyre, The Real Alan Turing (15th November, 2014)

(64) John Turing, He Should be Alive Today (22nd June, 2012)

(65) Alan Hodges, Oxford Dictionary of National Biography (2004-2014)

(66) Simon Singh, The Code Book: The Secret History of Codes & Code-Breaking (2000) page 189

(67) Alan Hodges, Alan Turing: the Enigma (1983) page 566

(68) David Leavitt, The Man Who Knew Too Much (2006) page 266

(69) Alan Turing, letter to Fred Clayton (24th January, 1952)

(70) Alan Hodges, Alan Turing: the Enigma (1983) page 576

(71) Lynsey Ann Lord, Joan Clarke Murray (2008)

(72) Alan Hodges, Alan Turing: the Enigma (1983) page 588

(73) Alan Turing, letter to Philip Hall (17th April 1952)

(74) Anthony Cave Brown, Bodyguard of Lies (1976) pages 814

(75) Wilmslow County Express (10th June, 1954)

Alan Turing - History

Alan Turing is not the most recognized of the legendary mathematicians in history, but he is among the most important. If it were not for Turing, computer science as we know it might not exist.

His innovative work in the development of the Turing Machine eventually led to insights in algorithms and computation, which lie at the core of modern computing. The Turing Machine itself can be considered one of the very early machines that set the stage for the all-purpose general computer.

Early Years

Alan Turing was born on June 23, 1912, in London, England. His father worked for the Indian Civil Service (ICS) and this led to his frequent traveling to British India. The elder Turing wanted his children to stay in London so Alan and his brother lived with a retired army couple during much of their childhood.

Even as a very young man, Turing showed tremendous academic promise. He went on to attend St. Michael’s Day School starting at the age of six. His instructors noticed he was an exceptionally bright young man and encouraged his pursuit of academic excellence.

As a teen he went on to enroll in the Sherborne School and then he entered higher education at King’s College, Cambridge. His achievements at the college were so pronounced that he made a fellow by the age of 22.

College Work

On Computable Numbers, with an Application to the Entscheidungsproblem was a stunning paper he wrote while he was in college. The focus of the paper was on the limits of proof and computation found in Kurt Gödel’s 1931 results. Within the paper written by Turing, it was noted that formal and simple hypothetical devices would be the best replacement for the universal arithmetic-based formal language found in the Gödel concept.

From these new language insights, the Turing machines would eventually emerge.

Turing’s Work during WWII

Alan Turing was also an expert at cracking codes and his skills were put to use for the British and Allied forces during the Second World War. The Polish had created a means of cracking codes, but there were problems with the method they employed. As a result, the Germans were capable of changing the codes when they found out they were being cracked.

Turing believed (correctly) that mathematics could play a major role in cracking codes. He wrote papers centered on the notion that both statistics and probability both aided in deciphering coded messages. He also focused heavily on Enigma rotors since these were used significantly to encrypt enigma messages.

The Turing-Welchman Bombe

Eventually, Turing devised a machine that would once and for all crack Enigma related codes. He did not work alone on this project and had quite a bit of help from Gordon Welchman, a mathematician who also specialized in code breaking. The two devised the Turing–Welchman bombe, which was an electromechanical device that effectively cracked the Enigma code. The end result was a machine fully capable of helping the British overcome numerous hurdles and roadblocks related to figuring out German codes.

Turing would also go on to help the armed forces break the code of the German Naval Enigma, which was a much more difficult code to break. Without Turing, the ability for British intelligence to prosecute the war would have been extremely difficult.

Post-WWII Work

When the Second World War ended, Turing continued to live and work in London. He invested a significant amount of time working on early computer systems. Specifically, he invested a great deal of time on the Automatic Computing Engine (ACE). In the middle of the 1940s, he produced a paper that discussed the concept of the stored-program computer and the work was many years ahead of its time.

In the late 1940s, he joined the staff at the University of Manchester where he served as the Reader at the Mathematics Department. In 1949, he was promoted to the position of Deputy Director of the Computing Laboratory. During this time, he worked on the software for the Manchester Mark I, one of the very first stored-program computers ever devised.

Turing’s Strange Death

On June 8, 1954, Alan Turing was found dead. He died after eating a cyanide-laced apple. He seemed be to recreating a scene out of one of his favorite stories – Snow White and the Seven Dwarfs.

The crime and punishment of Alan Turing

In 1952, Alan Turing, patriotic codebreaker and pioneer of computer science and artificial intelligence, was arrested, tried, and punished on the basis of his homosexuality. In this adapted extract from The Turing Guide, Jack Copeland walks us through the events leading up to his arrest and trial, which sentenced him to chemical castration.

Turing wrote a short story. Although only a few pages long and incomplete, it offers an intimate glimpse of its author. The central character — a scientist by the name of Alec Pryce, who works at Manchester University — is a thinly disguised Alan Turing. Pryce, like Turing himself, always wore what Turing described as “an old sports coat and rather unpressed worsted trousers.” Pryce, whose work related to interplanetary travel, made an important discovery in his twenties, which came to be called “Pryce’s buoy.” The nature of the discovery is left unexplained, and Pryce’s buoy is obviously a proxy for the universal Turing machine.

“Alec always felt a glow of pride when this phrase was used,” Turing wrote revealingly. “The rather obvious double-entendre rather pleased him too. He always liked to parade his homosexuality, and in suitable company Alec would pretend that the word was spelt without the ‘u.’”

Pryce, we are told, has not had a sexual relationship since “that soldier in Paris last summer.” Walking through Manchester, Pryce passes a youth lounging on a bench, Ron Miller. Ron, who is out of work and keeps company with petty criminals, makes a small income from male prostitution. He responds to a glance that Alec gives him as he passes, calling out uncouthly “Got a fag?”. Shyly Alec joins him on the bench and the two sit together awkwardly. Eventually Alec plucks up courage to invite the boy to have lunch at a nearby restaurant. Beggars can’t be choosers, Ron thinks meanly.

“Ronald” is an anagram of “Arnold,” and it was in December 1951 that Turing first met Arnold Murray, the Ronald Miller of his short story. Turing picked up Murray in Manchester’s Oxford Street and the two ate together. Their first time was a few days later at Turing’s house, Hollymeade, in Wilmslow. Afterwards Turing gave Murray a present of a penknife: probably the unemployed Murray would have preferred cash instead. The next time they had sex, Murray stole £8 from Turing’s pocket as he left Hollymeade in the morning, and not long after this the house was burgled.

Even though the finger of suspicion pointed at Murray and his seedy friends, Turing spent the night with him one more time. In the morning he led Murray to the local police station. Turing went in, but not Murray. In the course of reporting the burglary he gave the police a wrong description and this, as the newspaper reporter covering his subsequent trial wrote luridly, “proved to be his undoing.”

During questioning, Turing admitted to having had sex with Murray three times. The burglary dropped out of the picture, eclipsed by this sensational new information.

As the police knew all too well, each of the three occasions counted as two separate crimes under the antique 1885 legislation still in force — the commission of an act of gross indecency with another male person, and the reciprocal crime of being party to the commission of an act of gross indecency. Six criminal offences.

After Turing made his statement, he said to a police officer: “What is going to happen about all this? Isn’t there a Royal Commission sitting to legalise it?” But not until 1967 was homosexuality decriminalized in the UK.

Three weeks later, at the end of February 1952, Turing and Murray appeared in court. The charges were read out and both men were committed for trial. The court granted Turing bail of £50, but refused to let Murray out of custody. Following a distressing wait of more than four weeks, the trial was held in the quiet Cheshire town of Knutsford at the end of March. Turing pleaded guilty on all six counts, as did Murray. The mathematician Max Newman, Turing’s long-time friend, was called as a character witness. “He is completely absorbed in his work, and is one of the most profound and original mathematical minds of his generation,” Newman said. It must have been good to hear these words, even on such a black day.

Murray’s counsel attempted to shift the blame onto Turing, saying that Turing had approached Murray. If Murray “had not met Turing he would not have indulged in that practice or stolen the £8,” the barrister argued crassly. But his tactics worked: despite a previous conviction for larceny, Murray got off with 12 months’ good behaviour.

Turing’s own counsel hoped to steer the court away from a prison sentence, and alluded to the possibility of organotherapy: “There is treatment which could be given him. I ask you to think that the public interest would not be well served if this man is taken away from the very important work he is doing.” The judge followed the barrister’s lead, sentencing Turing to 12 months’ probation and ordering him to “submit for treatment by a duly qualified medical practitioner at Manchester Royal Infirmary.” It was not exactly the eulogy he deserved from the nation he had saved. Turing wrote in a letter, “No doubt I shall emerge from it all a different man, but quite who I’ve not found out.” He signed the letter “Yours in distress.”

The alternative of prison would probably have cost him his job, and with it his access to a computer. Already his arrest had cost him something else that mattered to him: as he told a friend, he would never be able to work for GCHQ again. One of his Bletchley Park colleagues, Joan Clarke, who stayed on as a peacetime codebreaker, confirmed that Turing visited GCHQ’s Eastcote site after the war as a consultant. But now Turing, the perfect patriot, had unwittingly become a security risk.

Jack Copeland FRS NZ is Distinguished Professor in Arts at the University of Canterbury, New Zealand, where he is Director of the Turing Archive for the History of Computing. He has been script advisor and scientific consultant for a number of recent documentaries about Turing. Copeland is the author of a number of books about Alan Turing, including The Turing Guide (OUP, 2017).

In 1950, Alan Turing Created a Chess Computer Program That Prefigured A.I.

Chess is one of the oldest, and most revered games of strategy and analysis in the world. It’s a game so intricate that some spend their entire lives trying to master it. Nearly 60 years ago, a new player entered the game–one powered not by human intelligence and dedication, but by lines of code on paper, written by computer scientist Alan Turing.

The most well-known chess-playing computer is IBM’s Deep Blue, which faced off against Russian chess grandmaster Garry Kasparov in a much publicized series of matches in February 1996. Deep Blue was not the first computer programmed for chess, however. That distinct honor goes to an algorithm named “Turbochamp,” which was written by famed British computer scientist, mathematician and cryptanalyst Alan Turing in the late 1940s.

Known by many historians as the �ther of computer science,” Turing first made a name for himself when he perfected the Bombe𠄺 mechanical device used by British intelligence to decipher encrypted messages sent using the German Enigma machine during World War II. Turing’s achievements are considered a turning point of the war.

Turing continued his work in the computer science field, even working with primitive forms of artificial intelligence. His work with A.I. quickly led him to tackle chess, which he saw as a way to test the true mettle of an artificial brain. (The term 𠇊.I.” wasn’t coined until 1956, two years after Turing’s untimely death).

An Enigma cipher machine that belonged to codebreaker Alan Turing at Bonham’s Auction House, New York City. (Credit: Spencer Platt/Getty Images)

Turing began working on his algorithm in 1948, before computers were even capable of executing complex calculations. Still, Turing pressed on and finished his code in 1950. The algorithm was crude. Its logic was based on just a few of the most basic rules of chess, and it was only able to “think” two moves in advance. To put that in context, Garry Kasparov, who is considered one of the best players in the world, has stated that he typically calculates three to five moves ahead, but can look ahead as many as 12 or 14 moves, depending on the situation.

Once the code was written, Turing set out to test it on a working computer. After failed attempts at implementing the algorithm using the Ferranti Mark I–the world’s first commercially available general-purpose computer–in 1951, Turing decided to demo the algorithm’s capabilities without using a computer at all.

He challenged his friend and colleague Alick Glennie, with the caveat that Turing would play the game using a paper-printed version of his code. When it was Turing’s turn to make a move, he would consult the algorithm and use its “logic” to decide which pieces to move, and where. Because he had to analyze every move as his program would, Turing took upwards of 30 minutes to work through the strategy each time his turn came. “Turbochamp “showed it was fully capable of playing against a human in chess𠅋ut not winning. Glennie defeated Turing in just 29 moves.

Turing never got to see his program executed by an actual computer. He died from cyanide poisoning in 1954–two weeks shy of what would have been his 42nd birthday. Turing had been prosecuted, and chemically castrated, due to his relationship with another man in 1952. Turing’s wartime triumphs and early artificial intelligence accomplishments fell in to obscurity. The British government didn’t declassify the work of Turing and his Bletchley Park colleagues until the 1970s, and Turing’s own record of the cracking of the Enigma code wasn’t published until the 1990s.

VIDEO: Garry Kasparov plays Turing’s “Turbochamp”

In June 2012, as part of the University of Manchester’s Alan Turing Centenary Conference, “Turbochamp” finally got a chance to prove its acumen in front of the world. The algorithm’s opponent that day? Garry Kasparov, of course.

The little program from 1950 was no match for the Russian grandmaster, who had won against IBM’s �p Blue” back in 1966, but later lost to an IBM supercomputer in 1997. The man who many think is the greatest chess player of all time mopped the floor with Turbochamp in just 16 moves. Afterwards, the victorious Kasparov paid tribute to the legendary programmer, stating: “I suppose you might call it primitive, but I would compare it to an early car—you might laugh at them but it is still an incredible achievement.”

“[Turing] wrote algorithms without having a computer—many young scientists would never believe that was possible. It was an outstanding accomplishment.”

Biography [ edit | edit source ]

Turing was born in Paddington, London, while his father, Julius Mathison Turing (1873–1947), was on leave from his position with the Indian Civil Service (ICS) at Chhatrapur, Bihar and Orissa Province, in British India. Turing's father was the son of a clergyman, Rev. John Robert Turing, from a Scottish family of merchants which had been based in the Netherlands and included a baronet. Turing's mother, Julius' wife, was Ethel Sara (née Stoney 1881–1976), daughter of Edward Waller Stoney, chief engineer of the Madras Railways. The Stoneys were a Protestant Anglo-Irish gentry family from both County Tipperary and County Longford, while Ethel herself had spent much of her childhood in County Clare.

Julius' work with the ICS brought the family to British India, where his grandfather had been a general in the Bengal Army. However, both Julius and Ethel wanted their children to be brought up in England, so they moved to Maida Vale,London, where Turing was born on 23 June 1912, as recorded by a blue plaque on the outside of the house of his birth, later the Colonnade Hotel.He had an elder brother, John (the father of Sir John Dermot Turing, 12th Baronet of the Turing baronets).

Turing's father's civil service commission was still active and during Turing's childhood years Turing's parents travelled between Hastings in England and India, leaving their two sons to stay with a retired Army couple. At Hastings, Turing stayed at Baston Lodge, Upper Maze Hill, St Leonards-on-Sea, now marked with a blue plaque.

Very early in life, Turing showed signs of the genius that he was later to display prominently. His parents purchased a house in Guildford in 1927, and Turing lived there during school holidays. The location is also marked with a blue plaque.

Turing's parents enrolled him at St Michael's, a day school at 20 Charles Road, St Leonards-on-Sea, at the age of six. The headmistress recognised his talent early on, as did many of his subsequent educators. In 1926, at the age of 13, he went on to Sherborne School, a well-known independent school in the market town of Sherborne in Dorset. The first day of term coincided with the 1926 General Strike in Britain, but he was so determined to attend that he rode his bicycle unaccompanied more than 60 miles (97 km) from Southampton to Sherborne, stopping overnight at an inn.

Turing's natural inclination towards mathematics and science did not earn him respect from some of the teachers at Sherborne, whose definition of education placed more emphasis on the classics. His headmaster wrote to his parents: "I hope he will not fall between two stools. If he is to stay at public school, he must aim at becoming educated. If he is to be solely a Scientific Specialist, he is wasting his time at a public school".Despite this, Turing continued to show remarkable ability in the studies he loved, solving advanced problems in 1927 without having studied even elementary calculus. In 1928, aged 16, Turing encountered Albert Einstein's work not only did he grasp it, but he extrapolated Einstein's questioning of Newton's laws of motion from a text in which this was never made explicit.

At Sherborne, Turing formed an important friendship with fellow pupil Christopher Morcom, who has been described as Turing's "first love". Their relationship provided inspiration in Turing's future endeavours, but it was cut short by Morcom's death in February 1930 from complications of bovine tuberculosis contracted after drinking infected cow's milk some years previously.This event shattered Turing's religious faith. He became an atheist. He believed that all phenomena, including the workings of the human brain, must be materialistic.

After Sherborne, Turing studied as an undergraduate from 1931 to 1934 at King's College, Cambridge, from where he gained first-class honours in mathematics. In 1935, at the young age of 22, he was elected a fellow at King's on the strength of a dissertation in which he proved the central limit theorem,despite the fact that he had failed to find out that it had already been proven in 1922 by Jarl Waldemar Lindeberg.

In 1928, German mathematician David Hilbert had called attention to the Entscheidungsproblem (decision problem). In his momentous paper "On Computable Numbers, with an Application to the Entscheidungsproblem" (submitted on 28 May 1936 and delivered 12 November), Turing reformulated Kurt Gödel's 1931 results on the limits of proof and computation, replacing Gödel's universal arithmetic-based formal language with the formal and simple hypothetical devices that became known as Turing machines. He proved that some such machine would be capable of performing any conceivable mathematical computation if it were representable as an algorithm. He went on to prove that there was no solution to the Entscheidungsproblem by first showing that the halting problem for Turing machines is undecidable: in general, it is not possible to decide algorithmically whether a given Turing machine will ever halt.

lthough Turing's proof was published shortly after Alonzo Church's equivalent proof using his lambda calculus, Turing had been unaware of Church's work. Turing's approach is considerably more accessible and intuitive than Church's. It was also novel in its notion of a 'Universal Machine' (now known as a universal Turing machine), with the idea that such a machine could perform the tasks of any other computation machine, or in other words, it is provably capable of computing anything that is computable. Von Neumann acknowledged that the central concept of the modern computer was due to this paper. Turing machines are to this day a central object of study in theory of computation.

From September 1936 to July 1938, Turing spent most of his time studying under Church at Princeton University. In addition to his purely mathematical work, he studied cryptology and also built three of four stages of an electro-mechanical binary multiplier. In June 1938, he obtained his PhD from Princeton his dissertation, Systems of Logic Based on Ordinals, introduced the concept of ordinal logic and the notion of relative computing, where Turing machines are augmented with so-called oracles, allowing a study of problems that cannot be solved by a Turing machine.

When Turing returned to Cambridge, he attended lectures given in 1939 by Ludwig Wittgenstein about the foundations of mathematics. Remarkably, the lectures have been reconstructed verbatim, including interjections from Turing and other students, from students' notes. Turing and Wittgenstein argued and disagreed, with Turing defending formalism and Wittgenstein propounding his view that mathematics does not discover any absolute truths but rather invents them.He also started to work part-time with the Government Code and Cypher School (GC&CS).

During the Second World War, Turing was a leading participant in the breaking of German ciphers at Bletchley Park. The historian and wartime codebreaker Asa Briggs has said, "You needed exceptional talent, you needed genius at Bletchley and Turing's was that genius."

From September 1938, Turing had been working part-time with the GC&CS, the British code breaking organisation. He concentrated on cryptanalysis of the Enigma, with Dilly Knox, a senior GC&CS codebreaker.Soon after the July 1939 Warsaw meeting at which the Polish Cipher Bureau had provided the British and French with the details of the wiring of Enigma rotors and their method of decrypting Enigma code messages, Turing and Knox started to work on a less fragile approach to the problem.The Polish method relied on an insecure indicator procedure that the Germans were likely to change, which they did in May 1940. Turing's approach was more general, using crib-based decryption for which he produced the functional specification of the bombe (an improvement of the Polish Bomba).

On 4 September 1939, the day after the UK declared war on Germany, Turing reported to Bletchley Park, the wartime station of GC&CS.[47] Specifying the bombe was the first of five major cryptanalytical advances that Turing made during the war. The others were: deducing the indicator procedure used by the German navy developing a statistical procedure for making much more efficient use of the bombes dubbed Banburismus developing a procedure for working out the cam settings of the wheels of the Lorenz SZ 40/42 (Tunny) dubbed Turingery and, towards the end of the war, the development of a portable secure voice scrambler at Hanslope Park that was codenamed Delilah.

By using statistical techniques to optimise the trial of different possibilities in the code breaking process, Turing made an innovative contribution to the subject. He wrote two papers discussing mathematical approaches which were entitled The Applications of Probability to Cryptography and Paper on Statistics of Repetitions,which were of such value to GC&CS and its successor GCHQ that they were not released to the UK National Archives until April 2012, shortly before the centenary of his birth. A GCHQ mathematician said at the time that the fact that the contents had been restricted for some 70 years demonstrated their importance.

Turing had something of a reputation for eccentricity at Bletchley Park. He was known to his colleagues as 'Prof' and his treatise on Enigma was known as 'The Prof's Book'. Jack Good, a cryptanalyst who worked with him, is quoted by Ronald Lewin as having said of Turing:

In the first week of June each year he would get a bad attack of hay fever, and he would cycle to the office wearing a service gas mask to keep the pollen off. His bicycle had a fault: the chain would come off at regular intervals. Instead of having it mended he would count the number of times the pedals went round and would get off the bicycle in time to adjust the chain by hand. Another of his eccentricities is that he chained his mug to the radiator pipes to prevent it being stolen.

While working at Bletchley, Turing, who was a talented long-distance runner, occasionally ran the 40 miles (64 km) to London when he was needed for high-level meetings,and he was capable of world-class marathon standards. Turing tried out for the 1948 British Olympic team, hampered by an injury. His tryout time for the marathon was only 11 minutes slower than British silver medalist Thomas Richards' Olympic race time of 2 hours 35 minutes. He was Walton Athletic Club's best runner, a fact discovered when he passed the group while running alone.

In 1945, Turing was awarded the OBE by King George VI for his wartime services, but his work remained secret for many years.

Within weeks of arriving at Bletchley Park, Turing had specified an electromechanical machine that could help break Enigma more effectively than the Polish bomba kryptologiczna, from which its name was derived. The bombe, with an enhancement suggested by mathematician Gordon Welchman, became one of the primary tools, and the major automated one, used to attack Enigma-enciphered messages.

Turing's most important contribution, I think, was of part of the design of the bombe, the cryptanalytic machine. He had the idea that you could use, in effect, a theorem in logic which sounds to the untrained ear rather absurd namely that from a contradiction, you can deduce everything.

he bombe searched for possible correct settings used for an Enigma message (i.e., rotor order, rotor settings and plugboard settings), using a suitable crib: a fragment of probable plaintext. For each possible setting of the rotors (which had of the order of 1019 states, or 1022 for the four-rotor U-boat variant),the bombe performed a chain of logical deductions based on the crib, implemented electrically. The bombe detected when a contradiction had occurred, and ruled out that setting, moving on to the next. Most of the possible settings would cause contradictions and be discarded, leaving only a few to be investigated in detail. The first bombe was installed on 18 March 1940.

By late 1941, Turing and his fellow cryptanalysts Gordon Welchman, Hugh Alexander, and Stuart Milner-Barry were frustrated. Building on the brilliant work of the Poles, they had set up a good working system for decrypting Enigma signals but they only had a few people and a few bombes so they did not have time to translate all the signals. In the summer they had had considerable success and shipping losses had fallen to under 100,000 tons a month but they were still on a knife-edge. They badly needed more resources to keep abreast of German adjustments. They had tried to get more people and fund more bombes through the proper channels but they were getting nowhere. Finally, breaking all the rules, on 28 October they wrote directly to Winston Churchill spelling out their difficulties, with Turing as the first named. They emphasised how small their need was compared with the vast expenditure of men and money by the forces and compared with the level of assistance they could offer to the forces.

As Andrew Hodges, biographer of Turing, later wrote, "This letter had an electric effect."Churchill wrote a memo to General Ismay which read: "ACTION THIS DAY. Make sure they have all they want on extreme priority and report to me that this has been done." On 18 November the chief of the secret service reported that every possible measure was being taken. The cryptographers at Bletchley Park did not know of the prime minister's response, but as Milner-Barry later recalled, "All that we did notice was that almost from that day the rough ways began miraculously to be made smooth." More than two hundred bombes were in operation by the end of the war.

Turing decided to tackle the particularly difficult problem of German naval Enigma "because no one else was doing anything about it and I could have it to myself". In December 1939, Turing solved the essential part of the naval indicator system, which was more complex than the indicator systems used by the other services.That same night he also conceived of the idea of Banburismus, a sequential statistical technique (what Abraham Wald later called sequential analysis) to assist in breaking naval Enigma, "though I was not sure that it would work in practice, and was not in fact sure until some days had actually broken". For this he invented a measure of weight of evidence that he called the ban. Banburismus could rule out certain sequences of the Enigma rotors, substantially reducing the time needed to test settings on the bombes.

In 1941, Turing proposed marriage to Hut 8 colleague Joan Clarke, a fellow mathematician and cryptanalyst, but their engagement was short-lived. After admitting his homosexuality to his fiancée, who was reportedly "unfazed" by the revelation, Turing decided that he could not go through with the marriage.

Turing by Stephen Kettle at Bletchley Park, commissioned by Sidney Frank, built from half a million pieces of Welsh slate.

Turing travelled to the United States in November 1942 and worked with US Navy cryptanalysts on Naval Enigma and bombe construction in Washington. He visited their Computing Machine Laboratory at Dayton, Ohio. His reaction to the American Bombe design was far from enthusiastic:

"It seems a pity for them to go out of their way to build a machine to do all this stopping if it is not necessary. I am now converted to the extent of thinking that starting from scratch on the design of a Bombe, this method is about as good as our own. The American Bombe program was to produce 336 Bombes, one for each wheel order. I used to smile inwardly at the conception of test (of commutators) can hardly be considered conclusive as they were not testing for the bounce with electronic stop finding devices".

—Alan Turing During this trip, he also assisted at Bell Labs with the development of secure speech devices. He returned to Bletchley Park in March 1943. During his absence, Hugh Alexander had officially assumed the position of head of Hut 8, although Alexander had been de facto head for some time—Turing having little interest in the day-to-day running of the section. Turing became a general consultant for cryptanalysis at Bletchley Park.

Alexander wrote as follows about his contribution:

"There should be no question in anyone's mind that Turing's work was the biggest factor in Hut 8's success. In the early days he was the only cryptographer who thought the problem worth tackling and not only was he primarily responsible for the main theoretical work within the Hut but he also shared with Welchman and Keen the chief credit for the invention of the Bombe. It is always difficult to say that anyone is absolutely indispensable but if anyone was indispensable to Hut 8 it was Turing. The pioneer's work always tends to be forgotten when experience and routine later make everything seem easy and many of us in Hut 8 felt that the magnitude of Turing's contribution was never fully realised by the outside world".

In July 1942, Turing devised a technique termed Turingery (or jokingly Turingismus) for use against the Lorenz cipher messages produced by the Germans' new Geheimschreiber (secret writer) machine. This was a teleprinter rotor cipher attachment codenamed Tunny at Bletchley Park. Turingery was a method of wheel-breaking, i.e., a procedure for working out the cam settings of Tunny's wheels. He also introduced the Tunny team to Tommy Flowers who, under the guidance of Max Newman, went on to build the Colossus computer, the world's first programmable digital electronic computer, which replaced a simpler prior machine (the Heath Robinson), and whose superior speed allowed the statistical decryption techniques to be applied usefully to the messages. Some have mistakenly said that Turing was a key figure in the design of the Colossus computer. Turingery and the statistical approach of Banburismus undoubtedly fed into the thinking about cryptanalysis of the Lorenz cipher, but he was not directly involved in the Colossus development.

Following his work at Bell Labs in the US, Turing pursued the idea of electronic enciphering of speech in the telephone system, and in the latter part of the war, he moved to work for the Secret Service's Radio Security Service (later HMGCC) at Hanslope Park. There he further developed his knowledge of electronics with the assistance of engineer Donald Bayley. Together they undertook the design and construction of a portable secure voice communications machine codenamed Delilah.[84] It was intended for different applications, lacking capability for use with long-distance radio transmissions, and in any case, Delilah was completed too late to be used during the war. Though the system worked fully, with Turing demonstrating it to officials by encrypting and decrypting a recording of a Winston Churchill speech, Delilah was not adopted for use.

Turing also consulted with Bell Labs on the development of SIGSALY, a secure voice system that was used in the later years of the war.

From 1945 to 1947, Turing lived in Hampton, London while he worked on the design of the ACE (Automatic Computing Engine) at the National Physical Laboratory (NPL). He presented a paper on 19 February 1946, which was the first detailed design of a stored-program computer.Von Neumann's incomplete First Draft of a Report on the EDVAC had predated Turing's paper, but it was much less detailed and, according to John R. Womersley, Superintendent of the NPL Mathematics Division, it "contains a number of ideas which are Dr. Turing's own".

Although ACE was a feasible design, the secrecy surrounding the wartime work at Bletchley Park led to delays in starting the project and he became disillusioned. In late 1947 he returned to Cambridge for a sabbatical year during which he produced a seminal work on Intelligent Machinery that was not published in his lifetime. While he was at Cambridge, the Pilot ACE was being built in his absence. It executed its first program on 10 May 1950. Although the full version of Turing's ACE was never built, a number of computers around the world owe much to it, for example, the English Electric DEUCE and the American Bendix G-15.

According to the memoirs of the German computer pioneer Heinz Billing from the Max Planck Institute for Physics, published by Genscher, Düsseldorf (1997), there was a meeting between Alan Turing and Konrad Zuse. It took place in Göttingen in 1947. The interrogation had the form of a colloquium. Participants were Womersley, Turing, Porter from England and a few German researchers like Zuse, Walther, and Billing. (For more details see Herbert Bruderer, Konrad Zuse und die Schweiz).

In 1948, Turing was appointed Reader in the Mathematics Department at the University of Manchester. In 1949, he became Deputy Director of the Computing Laboratory there, working on software for one of the earliest stored-program computers—the Manchester Mark 1. During this time he continued to do more abstract work in mathematics, and in "Computing machinery and intelligence" (Mind, October 1950), Turing addressed the problem of artificial intelligence, and proposed an experiment which became known as the Turing test, an attempt to define a standard for a machine to be called "intelligent". The idea was that a computer could be said to "think" if a human interrogator could not tell it apart, through conversation, from a human being. In the paper, Turing suggested that rather than building a program to simulate the adult mind, it would be better rather to produce a simpler one to simulate a child's mind and then to subject it to a course of education. A reversed form of the Turing test is widely used on the Internet the CAPTCHA test is intended to determine whether the user is a human or a computer.

In 1948, Turing, working with his former undergraduate colleague, D. G. Champernowne, began writing a chess program for a computer that did not yet exist. By 1950, the program was completed and dubbed the Turochamp.In 1952, he tried to implement it on a Ferranti Mark 1, but lacking enough power, the computer was unable to execute the program. Instead, Turing played a game in which he simulated the computer, taking about half an hour per move. The game was recorded.The program lost to Turing's colleague Alick Glennie, although it is said that it won a game against Champernowne's wife.

His Turing test was a significant, characteristically provocative and lasting contribution to the debate regarding artificial intelligence, which continues after more than half a century.

He also invented the LU decomposition method in 1948,used today for solving matrix equations.

Turing worked from 1952 until his death in 1954 on mathematical biology, specifically morphogenesis. He published one paper on the subject called The Chemical Basis of Morphogenesis in 1952, putting forth the Turing hypothesis of pattern formation (the theory was experimentally confirmed 60 years after his death). His central interest in the field was understanding Fibonacci phyllotaxis, the existence of Fibonacci numbers in plant structures. He used reaction–diffusion equations which are central to the field of pattern formation. Later papers went unpublished until 1992 when Collected Works of A. M. Turing was published. His contribution is considered a seminal piece of work in this field. Removal of Hox genes causes an increased number of digits (up to 14) in mice, demonstrating a Turing-type mechanism in the development of the hand.

In January 1952, Turing, then 39, started a relationship with Arnold Murray, a 19-year-old unemployed man. Turing had met Murray just before Christmas outside the Regal Cinema when walking down Manchester's Oxford Road and invited him to lunch. On 23 January Turing's house was burgled. Murray told Turing that the burglar was an acquaintance of his, and Turing reported the crime to the police. During the investigation he acknowledged a sexual relationship with Murray. Homosexual acts were criminal offences in the United Kingdom at that time,[103] and both men were charged with gross indecency under Section 11 of the Criminal Law Amendment Act 1885.[104] Initial committal proceedings for the trial were held on 27 February during which Turing's solicitor "reserved his defence".

Later, convinced by the advice of his brother and his own solicitor, Turing entered a plea of guilty.[105] The case, Regina v. Turing and Murray, was brought to trial on 31 March 1952, when Turing was convicted and given a choice between imprisonment and probation, which would be conditional on his agreement to undergo hormonal treatment designed to reduce libido. He accepted the option of treatment via injections of stilboestrol, a synthetic oestrogen this treatment was continued for the course of one year. The treatment rendered Turing impotent and caused gynaecomastia,fulfilling in the literal sense Turing's prediction that "no doubt I shall emerge from it all a different man, but quite who I've not found out". Murray was given a conditional discharge.

On 8 June 1954, Turing's housekeeper found him dead. He had died the previous day. A post-mortem examination established that the cause of death was cyanide poisoning. When his body was discovered, an apple lay half-eaten beside his bed, and although the apple was not tested for cyanide, it was speculated that this was the means by which a fatal dose was consumed. An inquest determined that he had committed suicide, and he was cremated at Woking Crematorium on 12 June 1954. Turing's ashes were scattered there, just as his father's had been.

The electronic connection

Turing worked on other technical innovations during the war – in particular, a system to encrypt and decrypt spoken telephone conversations.

Codenamed Delilah, it was successfully demonstrated using a recording of one of Winston Churchill's speeches, but was never used in action. However, it gave Turing hands-on experience of working with electronics, and led to a position at the National Physical Laboratory (NPL), where he worked on what he sometimes described as an ‘electronic brain’.

Scientist of the Day - Alan Turing

Alan Turing, a British mathematician, was born June 23, 1912. Turing is often called the “father of the modern computer,” although several others, especially John von Neumann, might be equally deserving of the title. A fellow at King’s College, Cambridge, Turing by 1936 had already proposed the idea of a universal computer – a Turing machine, a logical device that could perform any operation that was calculable. But when war threatened in 1938, Turing joined several other King’s mathematicians at Bletchley Park in Buckinghamshire (third image), where their task was to crack the codes of the German military. As I am sure almost everyone knows, German cryptographers had developed a powerful cipher machine called the Enigma (first image), which would produce an encrypted message that could only be read by another Enigma machine – assuming, that is, that all the rotors, wheels, and punchboard wires were properly set. Enigma encryptions were considered by the Germans to be unbreakable, and many British cryptographers tended to agree with that assessment.

Portrait of Alan Turing, photograph, 1951 (National Portrait Gallery, London)

Turing was not a cryptographer, but a theoretical mathematician, a logician, and one of his most unusual traits, for a theorist, was to believe that working on practical applications of mathematical logic was a worthy activity. He was totally absorbed by the effort to crack the Enigma ciphers. By 1941, the English had succeeded. If you have seen the film, The Imitation Game (2014), in which Turing is deftly played by Benedict Cumberbatch, you learned there that Turing almost singlehandedly built the bombe – that mechanical colossus with all the rotating cogs and cams that took in an Enigma cipher, clanked and churned, and spit out the clear text. We show here a replica of the bombe on display at Bletchley Park (fourth image). In truth, many others were involved as well, and the idea of the bombe actually came from the Poles, who created a preliminary machine, the bomba, in 1938, which Turing learned about before Poland was invaded by the Nazis. But Turing did play an important role as the first head of “Hut 8”, which attacked the problem of the German naval codes, and Hut 8 did manage to break enough ciphers to end the U-boat carnage in the Atlantic and shorten the war by several years, or so it is estimated.

Bletchley Park, Buckinghamshire, where British cryptographers during World War II successfully cracked the Enigma cipher, photograph, 2017 (photo by DeFacto, Wikimedia commons)

Aside from the universal Turing machine and the bombe, Turing has two more feathers in his cap that should be mentioned. In 1946, Turing was the first to propose that a computer might have its program written in the same language as its data, so that it could be easily re-programmed. This was a novel idea, since the few computers constructed to date, such as the ENIAC in the United States, had paper tape programs to go with their vacuum-tube brains. The first programmable computer was built in Manchester in 1948, where several other King’s mathematicians, including Turing, had moved after the War.

Replica of the bombe, the machine that could decipher Enigma messages, Bletchley Park Museum, Buckinghamshire (

Turing’s other great insight was to invent the field of artificial intelligence. In 1950, he published a paper in the journal Mind, in which he asked whether computers might eventually be able to think (below is the cover of the October 1950 issue, with Turing’s name at the top of the table of contents). Turing concluded that indeed they might. This was a rather shocking notion at the time, but Turing’s idea was that if a computer can do anything that is calculable, and if the human brain thinks by doing calculable logical operations, then there is nothing the brain does that a computer, in theory, could not replicate. It was in this paper that Turing proposed the now-famous Turing test, in which an interrogator remotely converses with a computer and a human and tries to tell them apart from their responses. If you cannot tell the human from the computer, the computer has passed the Turing test (the “imitation game”) and is a thinking machine. Another excellent film, Ex Machina (2014), employed the Turing test as a major plot element in its tale of artificial intelligence.

Cover of the October 1950 issue of Mind, which contains Alan Turing’s paper, “Computing machinery and intelligence.” (

Turing’s life had a sad end, as you know if you saw The Imitation Game. Turing was a homosexual at a time when homosexuality was a criminal activity in Britain. When his sexual proclivities were discovered in 1952, he was convicted of “gross indecency.” He avoided prison only by agreeing to a kind of chemical castration, which seems to have affected his ability to work, and in addition, cost him his top-secret clearance. Two years later, he took his own life by ingesting cyanide (although some think that that his death might have been accidental poisoning). He was 42 years old. It was not until 2013 that Turing was officially pardoned by the Queen, which means it took 60 years to exonerate one of Britain’s greatest war heroes and most brilliant mathematicians for a crime that should never have been a crime in the first place.

Statue of Alan Turing, detail, at Bletchley Park, Buckinghamshire, photograph, 2009 (photo by Sjoerd Ferwerda on Wikimedia commons)

A statue of a seated Alan Turing, fashioned in slate by Stephen Kettle, was installed at Bletchley Park in 2007 above we see a detail of just the head. You can see the complete statue here.

History Essay Example: Alan Turing

Alan Turing lived a short life, but during it, he made a lot of discoveries that helped to shape the world as we know it today. His technological achievements not only aided the Allies in World War II but also helped in the development of modern computers. Considering how much he contributed to the creation of a computer – a device that everyone heavily relies on nowadays – it is strange that his name is not famous all over the world.

Born in 1912, Turing paid a lot of attention to education since his very childhood, with science and mathematics as his primary focus. Turing’s solid efforts paid off and his published work leaded to recognition from fellow mathematicians while just in his 20s.

In 1939, Turing made a significant contribution to Allies’ victory during the World War II. Along with a group of mathematicians and cryptanalysts, Turing created the Bombe—a code-breaking machine used to intercept coded messages from the Nazi forces. This machine decoded thousands of messages monthly and supplied information that helped the Allies win the war.

After the war, Turing joined a group at the National Physical Laboratory working to create the first electronic computing device. Lacking resources, the group was unable to produce a machine as complex as Turing designed, and the first electronic computer was produced by Turing’s competitors (Copeland).

Turing may have lost the battle to produce the first computer, but he remained victorious. His work laid a foundation for computer development that researchers still acknowledge today. Rick Rashid, chief research officer at Microsoft Research, stated, “Alan Turing is one of the first people to establish what a computer was, and what computation meant” (Lanxon). Ultimately, Turing’s life demonstrates that one man’s determination can affect society significantly.

LGBT+ History Month: Alan Turing and his enduring legacy

Alan Turing was born in London in 1912 just two years before the First World War. Growing up in the aftermath of brutal international conflict, Turing’s parents were keen to ensure that their son was able to thrive within education.

His passion for learning became clear when at the age of 13, the 1926 General Strike prevented Alan from attending his first day of school. Determined not to miss it, Alan Turing cycled 60 miles on his bike unaccompanied, stopping overnight at an inn and attending school the next day.

Achievements and Hardships

It became clear from an early age that Alan Turing was a maths prodigy, and over the course of his life and career Turing pioneered mathematics and computer science, changing the way we see and understand the world. From altering the course of history by breaking the Enigma code at Bletchley Park during the Second World War, through to applying his practical war-time experiences to design the principles of which underlie modern computers, Alan Turing’s legacy has shaped the lives of millions of people.

However, Alan Turing faced much hardship during his life due to his sexuality. During Turing’s life, homosexuality was a criminal offence and Turing was convicted in 1952 of “Gross Indecency”. Alan Turing was faced with an impossibly cruel choice of imprisonment, or probation on the condition he underwent chemical castration. Turing died from suicide two years later.

More than a century since the birth of mathematician Alan Turing, much has changed within the social, political and cultural landscape of the UK. One of the defining markers of change has been the LGBT+ liberation movement, which began in the 1970s and campaigned for equal rights for the gay community.

Thanks to the efforts of activists, historians and politicians, Turing’s legacy has not been forgotten. In 2013,HM Queen Elizabeth II signed a pardon for Turing’s conviction with immediate effect. Since then, the Alan Turing Law has gone on to secure pardons for 75,000 other men and women convicted of similar crimes.

The Turing Scheme

Following in the footsteps of Turing’s passion for learning and education, and for being an internationalist, in December we announced the launch of The Turing Scheme. This pioneering £110 million programme will provide funding for around 35,000 students in universities, colleges and schools to study and work abroad, starting in September 2021.We want this scheme to address the barriers that prevent some students, particularly those from less advantaged backgrounds, from studying overseas and making life-changing opportunities across the world accessible to everyone studying in the UK. More information is available at

During the development of the Turing Scheme the department has engaged with the Turing Estate to ensure the Scheme honours his remarkable legacy.

There is still more to be done to protect the rights of LGBT+ communities across the world, and it is vital to remember the lives and histories of people who have in the past been marginalised by society. Though the atrocities Turing faced cannot be unforgotten, the extraordinary impact of Alan Turing’s life and lives on in the futures of young people in the UK.

Tragic times.

During Alan’s lifetime it was illegal to be gay in the UK, and in 1952 he was convicted for having a relationship with a man. Rather than go to prison for his ‘crimes’, Alan agreed to have a medical treatment designed to take away his romantic desires. Sadly, his criminal record also meant that Alan lost his job.

As a result, Alan became depressed, and sadly died in 1954. Thankfully, this homophobic law was abolished in 1967, and Alan received a Royal Pardon in 2013.

Watch the video: Alan Turing - betrayed by the country he saved (January 2022).