FILM: The Imitation Game - How much is true?

Turing's rebuilt bombe machine, called Christopher in the film, on display at Bletchley Park Museum

True: Alan Turing was a great genius. And he helped win the war and invent the computer ...

But he was not so socially awkward as the film shows him ... And that is not the only thing the film gets wrong ...


Historical events

False: The naming of the Enigma-breaking machine "Christopher" after Turing's childhood friend, with Turing the only cryptographer working on it while others either did not help or outright opposed it. 

In reality  this electromechanical machine was called "Victory" and it was a collaborative, not individual, effort. It was a British Bombe machine, which was partly inspired by a design by the Polish cryptanalyst Marian Rejewski. Rejewski designed a machine in 1938, called bomba kryptologiczna, which had broken an earlier version of Germany's Enigma machines by the Polish Cipher Bureau before the Second World War.

A new machine with a different strategy was designed by Turing in 1940 with a major contribution from mathematician Gordon Welchman, who goes unmentioned in the film, his contribution instead attributed to Hugh Alexander.

False: The building of only one machine, with Turing playing a large role in its construction. More than 200 British Bombes were built under the supervision of chief engineer Harold Keen of the British Tabulating Machine Company. None of them were built at Bletchley Park.

Turing's rebuilt bombe machine, called Christopher in the film, on display at Bletchley Park Museum

False: The overall plot arc in which the British cryptographers were stymied for the first few years of the war and then a sudden breakthrough enabled them to finally break Enigma.

In reality, the Polish cryptanalysts Marian Rejewski, Jerzy Różycki and Henryk Zygalski from the Polish Cipher Bureau had been breaking German Enigma messages since 1932. Their effort allowed the Poles to build replicas of German machines in Warsaw for the Polish secret service. 

Just before the war, the Polish secret service revealed their work to their French and British allies in a secret meeting on 26 and 27 July 1939, in Pyry near Warsaw. Thousands of men and women were working on the project by the time the war ended in 1945. 

False: The computing advances did not obviate the need for human labour, as the many teams of largely female operators certainly knew. Throughout the war, there were breakthroughs and setbacks when the design or use of the German Enigma machines was changed and the Bletchley Park code breakers had to adapt.

False: The breakthrough depicted in the film gives the impression that the Bombe was developed first, and only became effective later, after it was realised that deciphering could be made easier by looking for known or speculated items contained in an intercepted message, a practice known in cryptanalysis as employing a crib. 

In reality, the opposite was true: the use of cribs was the central attack model upon which the Bombe's principal design was based, rather than being an afterthought to the design.

The suggestion that Enigma was the only German cipher broken at Bletchley Park. The breaking of the Lorenz cipher, codenamed "Tunny", arguably made just as important a contribution to Ultra intelligence as the breaking of Enigma, and breaking Tunny was in many ways more difficult. 

Neither the Tunny effort nor its main contributors, mathematician W. T. "Bill" Tutte and electrical engineer Tommy Flowers, are mentioned in the film. The Colossus computer they built goes unmentioned by name in the film, although there is an implicit suggestion that Turing was responsible for it, which he was not.

False: The scene where the Hut 8 team decides not to use broken codes to stop a German raid on a convoy that the brother of one of the code breakers (Peter Hilton) is serving on, to hide the fact they have broken the code.In reality, Hilton had no such brother, and decisions about when and whether to use data from Ultra intelligence were made at much higher administrative levels.

False: The sequence in which Turing writes a letter to Churchill to gain control over the project and obtain funding for the decryption machine. Turing was actually not alone in making a different request with a number of colleagues, including Hugh Alexander, writing a letter to Churchill (who had earlier visited there) in an effort to have more administrative resources sent to Bletchley Park, which Churchill immediately did.

False: The recruitment of Joan Clarke as a result of an examination after solving a crossword puzzle in a newspaper.In reality, Joan Clarke was recruited by her former academic supervisor, Gordon Welchman, to the Government Code and Cypher School (GC&CS). Puzzles were used by Bletchley Park in recruitment but neither Turing nor Clarke were ever involved with them.

Turing's personality and personal life
 

False: The presentation of Turing's social difficulties as so severe as to suggest Asperger syndrome or some form of autism. While a few writers and researchers have tried to assign such a retrospective diagnosis to Turing, and it is true that he had his share of eccentricities, the Asperger's-like traits portrayed in the film – social awkwardness, difficulty working co-operatively with others, and tendency to take things too literally – bear little relationship to the actual adult Turing.

True: Despite enjoying working alone, Turing was sociable and had friends, was also viewed as having a sense of humour, and had good working relationships with colleagues.

False: The scenes depicting Turing's childhood friend, including the manner in which Turing learned of Morcom's illness and death.

False: The sequence, which brackets the whole film, in which Turing is arrested in 1951 when a detective suspects him of being a Soviet spy, which leads to the discovery that Turing is gay.Turing's arrest was in 1952. The detective in the film and the interview as portrayed are fictional. Turing was investigated for his homosexuality after a robbery at his house and was never investigated for espionage.

The suggestion that chemical castration made Turing unable to think clearly or do any work. Despite physical weakness and changes in Turing's body including gynaecomastia, at that time he was doing innovative work on mathematical biology, inspired by the very changes his body was undergoing due to chemical castration. While the physical changes distressed Turing, his friends did not notice any meaningful changes to his disposition or comportment in the period between the beginning of his castration and his death.

The scene in which Clarke visits Turing in his home while he is serving probation.There is no record of Clarke ever visiting Turing's residence during his probation, although Turing did stay in touch with her after the war and informed her of his forthcoming trial for indecency.

The statement that Turing committed suicide after a year of hormone treatment. In reality, the nature of Turing's death is a matter of considerable debate. The chemical castration period ended 14 months before his death. The official inquest into his death ruled that he had committed suicide by consuming a cyanide-laced apple. 

Turing biographer Andrew Hodges believes the death was indeed a suicide, re-enacting the poisoned apple from Snow White, Turing's favourite fairy tale, with some deliberate ambiguity included to permit Turing's mother to interpret it as an accident. However, Jack Copeland, an editor of volumes of Turing's work and Director of the Turing Archive for the History of Computing, has suggested that Turing's death may have been accidental, caused by the cyanide fumes produced by an experiment in his spare room, and that the investigation was poorly conducted.

Personalities and actions of other characters

False: The depiction of Commander Denniston as a rigid officer, bound by military thinking and eager to shut down the decryption machine when it fails to deliver results.Denniston's grandchildren stated that the film takes an "unwarranted sideswipe" at their grandfather's memory, showing him to be a "baddy" and a "hectoring character" who hinders the work of Turing. They said their grandfather had a completely different temperament from the one portrayed in the film and was entirely supportive of the work done by cryptographers under his command.

There is no record of the film's depicted interactions between Turing and Denniston. Indeed, before the war, Denniston recruited lecturers at Oxford and Cambridge, and Turing, Welchman, and others began working part-time for him then.

Turing was always respected and considered one of the best code-breakers at Bletchley Park and in short order took on the role of a leader there.

False: All the interactions between Turing and Stewart Menzies, head of the British Secret Intelligence Service. There are no records showing that they interacted at all during Turing's time at Bletchley Park.

False: An espionage subplot involving Turing and Soviet spy John Cairncross.Turing and Cairncross worked in different areas of Bletchley Park and there is no evidence they ever met. Alex Von Tunzelmann was angered by this subplot (which suggests that Turing was for a while blackmailed into not revealing Cairncross as a spy lest his homosexuality be revealed), writing that "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."

False: Hugh Alexander is said to have won the British Chess Championship twice near the beginning of the film. Although this is true, he won it once in 1938 and the second time in 1956, after the war.