Alan Turing & The Imitation Game

The Golden Globes and the BAFTAs are behind us, and the Academy Awards ceremony for the best films in 2014 will be held this Sunday 22 February. Leading with the way with the most nominations for an Oscar are Birdman and The Grand Budapest Hotel with nine nominations each, followed by The Imitation Game with eight nominations.

I saw The Imitation Game and I thought it was a stirring and persuasive film, particularly its portrayal of the last few years of the life of wartime cryptanalyst Alan Turing following his prosecution in 1952 for homosexual acts, and his death from cyanide poisoning in 1954. However the statement in the film credits that the film was ‘based on the true story’ stretched the claim to the limits of its meaning. There were so many inaccuracies in the film, particularly those that served to exalt Alan Turing’s role in the Second World War to quite ridiculous heights – as if that should have been necessary considering his genius and pivotal role – that the film is a sad distortion of history. For the film to have received eight nominations, including that for best picture and best adapted screenplay, says a lot about the superficiality of our emotions and our disregard for the truth. The quote from Mark Twain ‘never let the truth get in the way of a good story, unless you can’t think of anything better’ is most apt, and The Imitation Game is a dashing good story.

Bletchley Park and Ultra

The Cambridge mathematician Alan Turing played a key role in the allied victory in the Second World War in the cracking of German radio messages, or signals, which had been enciphered using Enigma machines. This decipherment yielded high-grade German military intelligence, dubbed Ultra, from ‘ultra secret’, which had a dramatic impact on the course and duration of the war. (Strictly speaking when one letter is substituted by another to make a message secret, it is a cipher, not a code, which is when letters or symbols are used to mean whole words or phrases. Therefore when codes or code breaking are spoken of it is usually ciphers and decipherment that are being referred to).

Turing started working part-time at Bletchley Park near Milton Keynes in Buckinghamshire in September 1938. Bletchley Park was the central site during the war of the government’s secret code and cipher school (GC&CS). Every one of the 12,000 staff who had ever worked at some point at Bletchley Park had signed the Official Secrets Act, and the government continued to enforce their silence long after the war was over. This was mainly because Britain’s code-breaking success had to remain secret during the Cold War with the Soviet Union, but also because Enigma machines were still in use around the world and Britain wanted to be able to read this signals traffic. Therefore the relatives of the staff at Bletchley Park never knew more than that they had done some kind of secret war work, or were told a cover story about clerical or statistical work. Winston Churchill, Prime Minister of the United Kingdom during the war referred to the staff at Bletchley as ‘The geese that laid the golden eggs and never cackled’. It was only with the publication of Frederick Winterbotham’s book The Ultra Secret in 1974, some thirty years later, that the public began to learn of the secret of Bletchley Park.

The Imitation Game

In the film, the Second World War has just broken out, and the British intelligence agency in September 1939 recruits Cambridge mathematician Alan Turing to join a team at Bletchley Park who are attempting to decipher Enigma messages sent by the German military, that cryptanalysts had thought unbreakable. Turing wants to build a machine to help crack the messages, but the head of Bletchley Park, Commander Alastair Denniston opposes this. Turing appeals to Winston Churchill for funding and is put in charge of the team. Turing sacks two members of the team, and recruits Joan Clarke, with whom he subsequently becomes engaged.

Turing successfully builds the machine – which he names Christopher after one of his childhood friends – that deciphers the messages. The deciphered messages, called Ultra, are used by the team to warn Britain’s armed forces of Germany’s detailed war plans, thus shortening the war. Some years after the war, Turing is prosecuted for indecency (at a time when homosexual acts were illegal) and he accepts chemical castration as an alternative to prison. He deteriorates physically and mentally with few people knowing of his crucial role.

The screenplay was written by American screenwriter and author, Graham Moore and was said to be based on the 527 page biography Alan Turing: The Enigma by Andrew Hodges. The main characters in the film and the actors who played them are Alan Turing (Benedict Cumberbatch), Commander Alastair Denniston (Charles Dance), and the other members of the team, Hugh Alexander (Matthew Goode), John Cairncross (Allen Leech), Peter Hilton (Matthew Beard), Joan Clarke (Keira Knightley), and Jack Good (James Northcote).

So what was wrong historically with the screenplay?

Characters in the Film

Turing’s social difficulties – he is brusque, arrogant and narcissistic, he doesn’t understand jokes, he avoids eye contact – are exaggerated in the film to the point of depicting him as being on the autistic spectrum. While it is true that Turing had his share of eccentricities, Turing had friends and was viewed as having a sense of humour with good working relationships with colleagues.

Hugh Alexander plays Turing’s boss at the start of the film, though he never was in real life. Turing joined Bletchley Park in 1938 before the outbreak of war and Alexander didn’t arrive until 1940 as until then he was head of the John Lewis research department. A better counterpart to Turing would have been Gordon Welchman, who was in charge of Hut 6 at Bletchley Park breaking German army codes, when Turing was in charge of Hut 8 breaking German naval codes. The two also worked together designing the code-breaking machines, called Bombes. But Welchman doesn’t appear in the film perhaps because Turing would not then appear so pre-eminent. Turing did not get involved in organisational matters at Bletchley Park. Welchman was the man who realised the necessity of setting up staff into three shifts to handle intercepts 24 hours a day. Hugh Alexander eventually took over the running of Hut 8 from Turing, and eventually became head of cryptanalysis at Bletchley.

Turing originally worked on the naval Enigma on his own and he does break it. He was joined by Tony Kendrick and Peter Twinn, who are not featured. Clarke, Alexander, Good and Hilton only joined later, in that order.

The film sets up Denniston, the operational head of Bletchley, as an antagonist to Turing, portraying him as an overbearing rigid officer bound by military thinking and eager to shut down the decryption machine when it failed to deliver results. Denniston’s grandchildren have said that the film takes an ‘unwarranted sideswipe’ at their grandfather in showing him as a ‘baddy’. He was a gentle man with a completely different temperament than the one portrayed in the film. There is no record of the film’s depicted interactions between Turing and Denniston.

The film places John Cairncross, the Soviet spy and possible ‘Fifth Man’ of the Cambridge spy ring, who was eventually caught in 1951, in Turing’s team. Cairncross was at Bletchley Park, but he was in a different section breaking a different cipher entirely. Turing’s biographer, Andrew Hodges, has said that it was ‘ludicrous’ to imagine that the two would even have met given that security was far too tight to allow it. 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’. The blackmail works as Turing covers up for the spy, for a while at least. This is wholly imaginary since concealing a spy would have been an extremely serious matter. It could amount to treason, and it of course slanders the real Alan Turing’s reputation.

Joan Clarke was not recruited by a crossword competition. The Telegraph newspaper did organise a competition to complete their crossword in less than twelve minutes, and successful contestants were then approached for a job at Bletchley. The scene in which the brilliant Cambridge mathematician Joan Clarke is snubbed and refused entry to a supposedly top-secret codebreaker’s examination because she is female, is entirely invented. How could anyone be in a top-secret building for a top-secret examination unless they had been invited, and how could the person in charge not know that one of the examinees was female?

The Polish Contribution 

Though there is a muttered line by Turing in the film about the ‘contribution of the Poles’, in reality their contribution was crucial. In 1932, code breakers in the Polish Cipher Bureau obtained one of the Enigma machines that were being used by German military units to encipher messages. One of them, Marian Rejewskie, deduced the internal wiring of the machine, and replicas of the Enigma machines were also made. The Bureau eventually broke the army and air force Enigma, though they didn’t break the naval messages. When the Germans increased the security of the machines, the Polish didn’t have the resources to tackle this. Five weeks before Poland was invaded by Germany in September 1939, three Polish mathematicians, Rejewskie together with Henryk Zygalski and Jerzy Różycki handed reconstructed Enigma machines and their techniques for decrypting ciphers to French and British military intelligence. Deniston was at one of the meetings. This enabled Britain to jump-start the reading of Enigma messages and to obtain for instance some forewarning of Germany’s plans for air raids in the Battle of Britain in late 1940. Welchman later said that ‘Ultra would never have gotten off the ground if we had not learned from the Poles, in the nick of time, the details … of the German military Enigma machine’ 

The Enigma Machine

Very early on in the film, Turing is shown an Enigma machine, and he mutters about ‘five rotors’. At that time the machine had only three rotors, and this would have been obvious to Turing. Two more rotors were introduced by the Germans later on in order to enhance security. Turing also says that German operators of the Enigma machine had to choose five random letters to include at the start of messages to be enciphered, when in fact the procedure was to choose three, which were then transmitted twice.

The detailed workings of the Enigma machine are explained here. To break the Enigma messages, the cryptanalysts at Bletchley Park exploited some fundamental weaknesses of the machine, such as that a letter could never be replaced, that is encrypted, to itself. You read how this was done here.

The Bombe

In the film, Turing designs and builds the Bombe, the code-breaking machine, and it is suggested that it is Turing’s computer. It was not a computer but an electro-mechanical machine first designed by Polish mathematicians in 1938 when it was called ‘bomba kryptologiczna’, the bomba part named after an ice-cream dish served at a Warsaw café. In practice a series of them, not just one, were connected and they worked in tandem. The British Bombe was actually supplied already built by the British Tabulating Co in March 1940 though to a complete re-design by Turing with some enhancements by Welchman. It was much more powerful and reliable than the Polish machines. The idea of the machine having diagonal connections was Welchman’s not Turing’s. Although the film implies otherwise, Turing knew exactly what the Bombe would do and how to use it. Hugh Alexander is shown trying to attack the Bombe, though in reality nothing like this ever happened. The detailed workings of the British Bombe are explained here.

Colossus

A much more important decrypting machine however came into use at Bletchley Park in 1942, but this is not mentioned in the film. Given it’s significance, some explanation is called for. Called Colossus, it was the world’s first digital program-controlled electronic computer, though there are other contenders for the title. Colossus was designed to break ciphers generated by the German Lorenz SZ 40 machine, which were much more secure than those of the Enigma machine. Messages from this machine, which was only used for messages from Hitler and the German High Command to their army field commanders, started to appear in 1941. A Lorenz machine was attached to each teleprinter in the army command posts across Nazi-occupied Europe. Incoming and outgoing messages to and from the teleprinter were routed via the machine. Each character in teleprinter form was a pattern of five pulses and pauses, and the machine automatically encrypted or decrypted the characters in the message in the same form. The ‘ciphertext’ was never seen by the German operators and it was transmitted automatically. Enigma was clumsy by comparison.

Brigadier John Tiltman, another cryptanalyst at Bletchley Park, identified the basis of how these teleprinter messages, nicknamed Tunny, were enciphered. Then a young Cambridge graduate called Bill Tutte, who had been rejected by Turing because he felt that Tutte would not fit in with the Enigma team, worked out the logical structure of the machine by Spring 1942, a feat which can be likened in importance to Turing’s earlier work on Enigma.

At first the messages had to be deciphered by hand, which took days and the decrypt was by then out of date. An experimental deciphering Heath-Robinson machine was built by Max Newman, the head of one of the Tunny-breaking sections (Newman had lectured Turing in 1935, which launched Turing on the research that led to the ‘universal Turing machine’). Although the machine was slow and unreliable, it proved that ‘tunny’ could be broken. But Tommy Flowers, a senior engineer at the Post Office Research Station at Dollis Hill who doubted that the Heath-Robinson would ever work properly, presented Newman in February 1943 with the alternative of a fully electronic machine.

Flowers’ suggestion was received with ‘incredulity’ at Bletchley Park. It was believed that the thousands of valves that it would require would make it too unreliable and that the war would be over before Flowers’ machine was finished. Newman therefore pressed ahead with a re-design of his Heath-Robinson machine. Meanwhile Flowers started building Colossus at Dollis Hill using his own money. As he said later he did it ‘without the concurrence of Bletchley Park’ and they ‘weren’t interested until they saw it [Colossus] working’.

The first machine was delivered to Bletchley Park in January 1944. Flowers eventually built nine more Colossus machines, and as a result, Bletchley Park deciphered 90% of the Tunny traffic intercepted in the last two years of the war. When the war ended, because Colossus was regarded as so secret, Flowers was not allowed to mention its existence, and he could not get funding for further work. He had no proof that he had developed anything. For his pains, Flowers was given £1,000 in recompense for his outlay in building Colossus, which he divided among his team at Dollis Hill. Although the volume of intelligence derived from Lorenz was much smaller than that from Enigma, it was much more important because it produced strategic intelligence.

Although Turing had introduced the Tunny team to Flowers and his use of probability in cryptanalysis contributed to what Colossus needed to do, contrary to some accounts, Turing was not involved in the building and development of Colossus. He was in any case away in the United States during the critical period at the beginning of 1943 when Flowers proposed his idea to Newman and worked out the design of Colossus on paper. As a 1945 report on Tunny stated, ‘Colossus was entirely the idea of Mr. Flowers’. A detailed history of Colossus can be read here.

As a result of Colossus, Britain was able to read the messages of the German High Command, in many cases at the same time as the enemy, and sometimes before them. The impact of these decrypts, which were part of Ultra, on the outcome of the war was profound. Whilst The Imitation Game was essentially about Alan Turing, and the Enigma and Bombe machines, it is disappointing that there was no mention at all about Colossus, and Tutte and Flowers.

Turing and Churchill

The film shows Turing writing a letter to Churchill in 1941 in order to gain control over the breaking of Enigma and to obtain funding for the decryption machine. In fact, Turing never sought to control the codebreaking, it was a lack of funding for more staff and more bombes that were the concerns. The real letter was signed not just by Turing but by three other senior cryptanalysts, Welchman, Alexander, and Stuart Milner-Barry, though it was written over Denniston’s head. Churchill immediately 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’. Almost straightaway, as Milner-Barry later recalled ‘the rough ways began miraculously to be made smooth’. In February 1942, Denniston was transferred elsewhere, and Commander Edward Travis, Denniston’s deputy, took over and re-organised Bletchley.

How Ultra Was Used

The film has a scene with a chart on the wall in Hut 8 showing the latest positions of all Atlantic convoys. The Hut 8 team decides not to use the decoded messages to stop a German raid on a convoy that the brother of one of team, Hilton, is serving on, in order to hide the fact they have broken the Enigma code. This is all entirely invented.

Firstly, the naval charts would have been in the map room of the Navy’s command centre in Liverpool that was as closely guarded as Bletchley Park, as were the army and air command centres elsewhere. Turing’s team had no input into how Ultra information was to be used. The decrypted messages were passed to MI6, which operated Special Liaison Units (SLU) attached to major army and air force commands, though highly important messages were sent directly to Churchill, usually with a covering note from Menzies. The SLUs disseminated the Ultra intelligence to field commanders. Information of interest to the navy was in the early days passed to the Operational Intelligence Centre of the Admiralty. The SLUs were supervised on behalf of MI6 by Group Captain Frederick Winterbotham, the author of The Ultra Secret in 1974.

It is true however that the sources of Ultra intelligence had to be safeguarded to avoid the Axis command realising that their ciphers had been broken. For example ‘spotter’ planes and submarine patrols were sent out to ‘search’ for Axis ships. When the spotter’s radio transmissions were observed by the Axis forces, they concluded their ships were being found by conventional reconnaissance. This lead the Axis to believe the Allies had far greater numbers of submarines and reconnaissance aircraft than they actually had. Other search missions would be sent out to other areas, so that crews would not begin to wonder why a single mission found the Axis ships every time. On more than one occasion Churchill made the decision over the use of Ultra where no other sources of intelligence were available. Though in real life Hilton had no brother, the film did illustrate a real enough example of the quandary that users of Ultra could be placed in.

Turing’s Prosecution

The plot in the final section of the film rests on a fictional Detective Nock (Rory Kinnear) pursuing Turing because he suspects him of being another Soviet spy, and he accidentally uncovers his homosexuality in the process. In real life, Turing himself reported a petty theft to the police, but changed details of his story to cover up the relationship he was having with the possible culprit, Arnold Murray. The police did not suspect him of espionage, and Turing would never have disclosed even the existence of Bletchley Park to a detective.

As a result of his conviction, Turing’s security clearance was removed and he was barred from his cryptographic consultancy for the Government Communications Headquarters (GCHQ), the British signals intelligence agency that had evolved from GC&CS. He was also denied entry into the United States. He was of course prevented by the Official Secrets Act from discussing his work at Bletchley Park.

Less Important Fictions

The first bombe used to decipher Enigma messages was called Victory, not Christopher as in the film.

Unlike in the film, Turing proposed to Clarke not to help her escape from overbearing parents, but because they liked each other. According to Hodges, when Turing ended the engagement, ‘it was neither a happy nor an easy decision, but it wasn’t the ultimately violent confrontation depicted in The Imitation Game, either’. The final scene, in which Clarke visits Turing during his probation, is invented.

Turing is also shown as interacting with Stewart Menzies, head of the British Secret Intelligence Service (also known as MI6) who also had responsibility for Bletchley Park, first of all in a tea shop and then in Joan Clarke’s flat. There is no record of Menzies and Turing having met during Turing’s time at Bletchley Park.

Despite the scene showing military police rifling through his desk at Bletchley Park, there is no evidence that the military police had anything to do with Turing either during the war or in the post war period.

Detective Nock was fictional. In reality, there were two detectives, Mr Wills and Mr Rimmer. Incidentally Nock uses Tipp-Ex in the film, although it didn’t exist until 1959.

At the end of the film, the team make a big bonfire at Bletchley Park and all the documents were burnt on Churchill’s orders, although in reality Turing had left Bletchley Park by then. He had spent five months in the United States in 1942/3, and by 1943 he was a general consultant for cryptanalysis at Bletchley Park.

At the end of the film, it claims that work done at Bletchley Park was kept secret for 50 years, that is until 1995. In fact, the first major revelations about Bletchley Park were as mentioned above in Frederick Winterbotham’s book The Ultra Secret published in 1974. There seems no reason to exaggerate the lapse of time?

Media Criticisms

Whilst the film was very well received by most reviewers, which is reflected in the Oscar nominations, some newspaper critics didn’t agree.

Tim Robey of the Telegraph says the film is ‘about a human calculator which feels … a little too calculated. It is a diligent mid-century biopic, with cookie-cutter screenwriting and a lacquered, nominate-me-for-everything sheen, that manages to feel like a series of stories we’ve heard before, following the familiar contours of other films as if with tracing paper’.

Alex von Tunzelmann of the Guardian said that 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, the film ‘must be sent straight to the bottom of the class’.

In response to criticism of the historical inaccuracies in the film, the screenwriter Graham Moore argued that The Imitation Game merely shows the ‘natural conflict of people working extremely hard under unimaginable pressure’ and he paid tribute to Denniston as being ‘one of the great heroes of Bletchley Park’.

An Open Letter

In an open letter to ‘Her Majesty’s Government’ published in a number of newspapers at the end of January 2015, the signatories which include Benedict Cumberbatch, Stephen Fry, Peter Tatchell, the director of The Imitation Game, Morten Tyldum, and Turing’s niece, Rachel Barnes, urge the British government to pardon thousands of gay men convicted of gross indecency. Their argument is that as British Prime Minister Gordon Brown made an official public apology in 2009 on behalf of the British government for ‘the appalling way in he [Turing] was treated’, and Queen Elizabeth II granted Turing a posthumous pardon in 2013, then all those who were convicted of a crime because of their sexuality should be pardoned, an act that could wipe clean the records of 15,000 men still alive.

The letter states ‘Alan Turing was one of the greatest heroes of the twentieth century, a man whose work on the machines that deciphered the Enigma codes helped win World War II and who was pivotal in the development of modern computers. Winston Churchill said Alan Turing ‘made the single biggest contribution to the Allied victory in World War II’ ‘.

Although a number of sources attribute this statement to Winston Churchill, both The Churchill Centre and Turing’s biographer, Andrew Hodges, have said they know of no documentary evidence to support this claim or of the date or context in which Churchill supposedly said it, but perhaps this is being uncharitable.

Did Bletchley Park Shorten the War?

Certainly it has been claimed that the work at Bletchley Park, and particularly the influence of Ultra, dramatically shortened the war in Europe, and that Turing’s pivotal role in cracking intercepted coded messages enabled the Allies to defeat the Nazis in many crucial engagements, including the Battle of the Atlantic.

But the actual assessments, whether from primary sources or by wartime leaders, military analysts or historians, are much less definitive. Winston Churchill was reported to have told King George VI, when presenting Stewart Menzies to him ‘it is thanks to [Ultra] … put into use on all the fronts, that we won the war’. Winterbotham quoted the western Supreme Allied Commander, Dwight D Eisenhower, at the end of the war, as describing Ultra as having been ‘decisive’ to Allied victory, though Eisenhower in his letter to Menzies in July 1945 says less precisely that the intelligence coming from Bletchley Park ‘saved thousands of British and American lives and, in no small way, contributed to the speed with which the enemy was routed and eventually forced to surrender’.

Harry Hinsley, who was the leading expert on the decryption and analysis of German wireless traffic at Bletchley Park and the official historian of British Intelligence in the Second World War, is often quoted as saying that Ultra shortened the war ‘by not less than two years and probably by four years’. However in his book Codebreakers: the Inside Story of Bletchley Park he just says that ‘historians who are concerned only with the war as it was must ask why it went as it did, and they need venture only a reasonable distance beyond the facts to recognise the extent to which the explanation lies in the influence of Ultra’.

Conclusion

The film suggests that the code-breaking work at Bletchley Park was the effort of a small group of cryptographers who were stymied in the first years of the war until Turing suddenly came up with a breakthrough that allowed them to break Enigma. Progress was actually made right from the beginning of the war in 1939 and thousands of people were working on the project within a few years.

The work that Turing did during the war was pioneering, and his genius was critical to the outcome. Alexander said in 1945:

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 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.

You can read more about Turing’s role at Bletchley Park and his wider influence in the development of computers here.

Surely Alan Turing’s life is compelling enough without film makers having to exaggerate his influence even further by re-inventing history.

Jerry Roberts, one of the four original members of  the unit at Bletchley Park who were given the task of decrypting Tunny, has said ‘I say there were three heroes at Bletchley – you can’t really put one above the others. Tommy Flowers founded the computer age we live in. Without Turing we’d all be speaking German by now, and Bill Tutte … we’ll he was a forgotten hero’.

Biopics have a useful role as the most popular way to find out about a subject. Isn’t it better to get to know more about Alan Turing no matter how many details The Imitation Game gets wrong? But more than 10,000 people were employed at Bletchley Park towards the end of the war working on a huge variety of enemy codes. At one point over 4,000 messages were being decrypted each day. There were many brilliant people there. Their work was extremely complex and challenging beyond our understanding. Alan Turing played a pivotal role in the eventual winning of the war, but there were other giants as well.

I feel that way in which Turing was portrayed in The Imitation Game may lead many filmgoers into believing that he single-handedly swung the war in our favour. Turing was much more than the hero of a film. The real story can be found in Hodges’s biography.

Final Word

Near the end of the final chapter of his biography of Turing, Andrew Hodges says:

Within his sphere he was the grand master; politically he was as he described himself in 1941: Churchill’s obedient servant. But he had never wanted to be the focus of the modern world. It had been his trouble all along that, although driven by the desire to do something, he wanted to remain ordinary, to be left alone in peace. These were incompatible goals …

Postscript

The Imitation Game was awarded one Oscar: Graham Moore for best adapted screenplay!

Here is another post about the misuse of history.