The Imitation Game: Fact and Fiction

Last weekend saw the release of ‘The Imitation Game’ in which Benedict Cumberbatch and Keira Knightley star as Alan Turing and Joan Clarke, codebreakers that helped change the course of the Second World War. Amongst an ensemble cast, the story of Turing is told in three parts; his school days, Bletchley Park and his final, desperate years in Manchester.


To many of us in the technical community, the story of Alan Turing is well known; a tragedy of a tortured genius who saved a world that may well have killed him in return. With this new film, the story of Alan Turing can reach a wider audience and his name will hopefully become as common-place as it deserves to be.

Rather that just do a straight review of the film, I thought it might be interesting to compare the facts with this new dramatisation. As I said to a friend, as we dissected the movie over a couple of drinks, my perfect Bletchley Park film would probably be five hours long, have way too many characters and probably be as dull as dishwater in order to get all the facts straight. I have no problem with artistic license to get the story told in an accessible way, without straying into dumbed-down territory. After all, this is Hollywood, not an exhaustive documentary.

For a great example of artistic license at work see the Tony Wilson bio-pic “24 Hour Party People”, directed by Michael Winterbottom. In Wilson’s own commentary track on the DVD, he has a problem with nearly everything that’s done, not only depicted events but even the layout of the furniture in his office. The result is hysterically funny but towards the end he observes “Never have so many lies been told to tell one overall truth”.

Of course it’s not exactly a spoiler to say that Enigma was broken, the Allies won the war and Turing met a tragic end but if you haven’t seen the film you may not wish to proceed.

Does the film get the correct message across?

Yes. The message that Turing did an amazing thing, that no-one else thought possible and was treated horrifically by the government is well-stated and on-point. Much of the story is dramatised, characters are merged and scenes invented but the overall message is clearly there.

A structural problem with The Imitation Game is exactly which story it wants to tell. Is the film about Alan Turing? Well, yes, of course, but what aspect of him? The script takes a direct, uncomplicated view of certain eras of his life. Curiously, his time at Cambridge before the war is omitted as is much of his final years. His personal struggles are brilliantly communicated by Alex Lawther as the young Turing, whose genius and passions are awaked by his friend Christopher Morcom. There was certainly much opportunity to explore his personal life in the Cumberbatch sections of the film, but little is made of it, focussing on his work instead. This is certainly not the story of Bletchley Park, as its focus is far too narrow, and it’s not Turing’s achievements as no mention is made of his later work in biology or computing (although I’m assuming that the machinery we see towards the end of the film represents the Pilot ACE project).

What we are left with are some key moments of Turing’s life. This is an attempt to explain what drove him, what he achieved and how it all ended, which it does very well, in a Hollywood way. That said, it should not be considered a proper bio-pic just as with Downfall, the captivating story of Hitler’s last months, which was based on recollections and used many invented scenes.

Alan Turing was difficult to work with

Just as portrayed in the film, he was renowned for rubbing people up the wrong way and acting in a spiky, impatient manner. Cumberbatch portrays this exceptionally well although the script lets him down a little and he is danger of becoming typecast as the socially-inept genius. There are attempts at humour (Turing trying to grasp the concept of ‘Lunch’ much to the exasperation of his colleagues), but this reminded me a little too much of Sherlock and a lot of the Sheldon Cooper character from The Big Bang Theory (Although to learn that Cooper was based on Turing in the first place would come as no surprise). Still, in our showing these scenes certainly got the laughs they were aiming for.

It’s a shame more wasn’t made of his true eccentricities, such as riding into Bletchley Park wearing a gas mask (hay fever) or storing silver ingots for post-war financial security and then forgetting where he buried them (they’re still missing). There is actually was a lot of material to work with.

Alex Lawther, who plays Turing during his school years is spellbinding and I hope come January he has plenty of Oscar talk around him. For me probably the most affecting moment of The Imitation Game is the scene in which the young Turing learns of his beloved Christopher’s death. He does an amazing job of conveying his vulnerability and bottled-up pain throughout. And yes, his mother really did refer to him as an ‘odd duck’.

Commander Denniston wasn’t Tywin Lannister

Alistair Denniston was commander of Bletchley Park until 1942. He was, by all accounts, a much calmer, softly spoken man than Charles Dance portrays. I believe the reason for this change to Dance’s Game of Thrones character is to give Turing and his team a nemesis, as the true enemy is unseen. Denniston was eventually replaced by Edward Travis who probably had more in common personality-wise with Dance’s Denniston. Travis does not feature in the film.

Enigma had already been broken when Turing joined Bletchley Park

The ‘interview’ scene with Turing, despite being quite funny, is pure fiction designed to introduce the viewer to the concept of Enigma. In fact, the military version of Enigma (it had been on sale as a commercial device) was broken in Poland by 1936 and other versions earlier than that. So, breaking Enigma was not considered ‘impossible’ as Dance’s Denniston states, although that may well have been the opinion held with regard to the naval Enigma network, which I think this scene references. Amongst others, Dilly Knox and his team broke Enigma time and time again contributing vital intelligence to the war effort.

Turing’s crucial role was in the industrialisation of codebreaking. Although Enigma could be broken by hand, it was a slow process and very easy to find yourself down a rabbit-hole. Turing’s invention revolutionised this process in a way no-one else had imagined.

There was more than one Enigma network

This is an omission from the screenplay that surprised me. There were over 200 Enigma networks in use at the height of the war, all with different settings. If you broke one, that was no help whatsoever with the others. Every day, at midnight, 200-plus new settings came into force. Turing specialised in the naval codes including the seeming impenetrable submarine codes that forms one of Bletchley Park’s greatest stories and is only alluded to in the film. Maybe it would have added significant running time in order to do a good job and this was a film about Turing, not Bletchley Park.

There was more than one Enigma machine

Enigma, just like any technical device today, was constantly enhanced during the course of the war. Many different models existed, some specially designed for the task in hand. Critically, these often featured different wiring and configurations to make them harder to break. Most fearsome of all was the M4, used by the German navy’s Atlantic ‘wolfpack’ fleet. Its introduction caused an intelligence blackout and resulting losses brought the Allies closer to losing the war than at any other point. The capture of an M4 by HMS Bulldog and then a settings book by HMS Petard are some of the most amazing stories of the Second World War (and completely misrepresented by the film U-571). With this information, Turing’s machine was successfully altered to crack the M4 and prevent disaster.

Bletchley Park was a lot bigger than portrayed

There is a quote midway through the film that goes along the lines of “We’re five people in a room trying to win the war”. That’s a little disingenuous to the 9,000 people that worked at Bletchley Park at its peak. Three shifts, 3,000 a shift, 24 hours a day. Yes of course, many of these were clerical and support staff but there were many more codebreakers than portrayed in the film. Many have had their characters merged to simplify the storytelling (we’ll get to that).

Bletchley Park didn’t just break Enigma

Again, this is an Alan Turing story, so Enigma is at the forefront. It may interest you to know that many different types of cipher were broken by Bletchley Park during the war. Not just German ones either. Italian and Japanese codes were routinely cracked as were the different types used by Germany. The Lorenz cipher, used by Hitler himself, was an order of magnitude more complicated than Enigma and was broken in 1941 by John Tiltman. This set in motion a chain of events that resulted in the building of the world’s first semi-programmable computer, Colossus.

Turing’s machine had a name

Turing’s named his machine a ‘Bombe’. The name is believed to come from the Polish machine he refers to in the film. The story goes that the Polish codebreakers named it after their favourite ice-cream dessert.

…and ‘Victory’

I’ve never heard of a machine called ‘Christopher’. As I understand it, the first Bombe was called ‘Victory’. This could a reference to a prototype, but I’ve not heard of it before.

There wasn’t one Bombe

In fact there were hundreds. The film correctly places Turing’s machine in Hut 11. Six Bombes were based there and over 200 more were based at Stanmore and Eastcote, two of Bletchley Park’s 300+ ‘out-stations’. A refined American design of the Bombe later produced well over 100 models, all based in the USA.

Turing designed the Bombe, but didn’t build it

The Bombes were built by The British Tabulating Machines Company in Letchworth. It was an industrial-scale process. Funny thing is, the workers had no idea of the true purpose of the machines and complained that they should be fighting rather than building fancy calculators.

The engineering work of the Bombe was undertaken by Harold ‘Doc’ Keen (later versions were known as ‘Keen Machines’). He’s sadly omitted in the film, although a man is seen in a long engineer’s coat (and later complaining to Denniston) but he is not named as Keen on the credits. Turing himself was not much of a mechanic and struggled to even mend his bike, which he rode by constantly pedalling back and forward to avoid a damaged link in the chain.

Hugh Alexander didn’t invent the Diagonal Board

Turing’s Bombe was speeded-up five-fold by the ‘diagonal board’ design. This work was done by Gordon Welchman. He is often cited as an equal co-creator of the Bombe but in the film, is merged with Hugh Alexander, effectively writing him out of history. I must admit this jarred with me as Welchman contributed so much to the work of Bletchley Park.

Turing really did write directly to Churchill

…but not alone. Again, Gordon Welchman is omitted and he is believed to be the primary author of this letter. Churchill had overseen an earlier incarnation of Bletchley Park, Room 40, whilst serving as First Lord of the Admiralty. He understood the importance of codebreaking and intelligence. It’s true that Turing was put in charge of Hut 8, although Hugh Alexander ran things day-to-day, but that didn’t place him in charge of some of the characters we see in the film. Churchill, upon reading the letter, instructed his Chief of Staff; “give them everything they ask for and report back to me directly”.

They didn’t use Enigma machines

Of course, the film shows our heroes using Enigma machines as the audience needs to see and have an appreciation of them. As Bletchley Park only had precious few captured Enigma machines, they modified British Typex cipher machines to work identically to Enigma.

Denniston knew all about the Enigma breaks

Probably the least accurate part of the film covers what happens after Turing’s machine breaks its first Enigma message. The idea that MI6 knew about Enigma breaks and not Commander Denniston didn’t is a bit ludicrous. As I have mentioned, Enigma was already being read at that point.

Turing never had any say on how intelligence was used

The concept of the moral dilemma of how to use intelligence without giving the game away was a very real one. Some extremely hard decisions had to be made in order to protect the secret that Enigma was fallible (contrary to popular belief, the bombing of Coventry was not one of them – the intelligence was gathered too late to make any practical use of it). Turing and the team portrayed were only tasked with producing meaningful intelligence from decrypted messages but that was the end of it. Decisions on ‘Ultra’ intelligence were made at the highest levels of government and military, often by people who knew little or nothing of its true source.

John Cairncross was a spy

Cairncross did indeed steal decrypted messages and hand them over to a spymaster in London. This was never proven so he was never prosecuted, just pushed aside as suspicions were there. He was later discovered to be part of the Cambridge spy ring and confessed to being a spy in 1951. There appears to be no historical basis for the double-agent story and it’s not clear whether MI6 had any idea of this deceit.

The team didn’t really work together

Codebreaking was split into two operations, decryption and analysis. Huts worked in pairs to perform these tasks and each pair was assigned specific Enigma networks. Turing’s office was in Hut 8, which handled decryption for the naval networks and worked in tandem with Hut 4, processing the raw decrypts not only into English but also parsing it into useful information. Cairncross was in Hut 6, working on intelligence from the German army and air force decrypts produced by Hut 3. There’s little doubt they collaborated but probably not in the way portrayed on film.

Cribbing was in widespread use

Turing’s ‘Eureka’ moment in the bar is strictly for dramatic effect. In the scene, Turing realises that guessing a piece of the message would help eliminate billions of possible settings from the Bombe’s work, speeding it up by an order of magnitude. In fact, the Bombe was designed around the concept of cribbing which was already being used for manual breaks into Enigma. The story about the German operator’s girlfriend, Cilly, is true and was of great help. It’s also true that Y Station (Wireless intelligence radio station) operators had German counterparts who they could recognise by the way they operated the morse key. This would allow, as stated in the film, for them to identify weather station reports and get a head-start on the settings for the day. And yes, a lot of German operators signed-off with ‘Heil Hitler’, so the last ten letters of an Enigma message were often known.

Yes, they had a bar and social events

Although the bar we see in the film is actually the mansion’s billiard room (the bar is next door), Hut 2 was often used as an informal ‘pub’. Bletchley Park also boasted a theatre group, rounders tournaments, choirs and a fencing club.

Women and men did work together

The idea that men and women could not work together at Bletchley Park is not true. Bletchley Park was a very-forward thinking place, tolerating many things (including Turing’s homosexuality, which was common knowledge) that would be deemed inappropriate in everyday society. Many codebreaking teams included women as a matter of course, including Mavis Batey who made several critical Enigma breaks by hand under the stewardship of Dilly Knox. Of course, it wasn’t perfect. They didn’t get paid as much and it was harder for them to progress through the ranks.

Alan Turing and Joan Clarke did get engaged

This aspect of the film seems to be pretty spot-on as I understand the story.

Bletchley Park did recruit using crossword puzzles

The Telegraph held a crossword competition as portrayed in the film but it was Mavis Batey who was recruited using this method, not Joan Clarke. Clarke had been working on Banburismus sheets when her desk was moved into Turing’s office due to space constraints. Turing realised her potential there, and also found a soulmate.

Turing wasn’t trying to build his Universal Machine

Clarke asks Turing if he trying to build his ‘Universal Machine’, a plot device to show that she is capable of understanding his work. He indicates that he is, but that isn’t the case. The Universal Machine described in his paper ‘On Computable Numbers’ is more of a thought experiment than a design for a real machine. A true Universal Machine would require an infinite supply of memory (in his description, paper tape) to work, so it could never be built (although you can scale it down to what we call – as stated in the closing credits – computers). What this idea revealed to world was that a computational machine could be built to tackle a huge range of complex problems. In writing this paper, Turing invented computer science.

Bletchley really did end in bonfires

There’s always going to be holes in our knowledge of Bletchley Park as so much information was destroyed to ensure absolute secrecy. They really were instructed to burn as much as possible. Out of all 200+ Bombes built, none remain.

He would never have told a police officer about Bletchley Park

It’s just a standard narration device. All members of the Government Code & Cypher School signed the Official Secrets Act and were left in no doubt about the importance, and potential consequences of their actions.

The end credits are problematic

The film closes with a sequence of titles (about nine in all) that close off the story from the point of the final scene, as we see a hollow Turing, his mind decaying from the hormone treatment he has been forced to take. One caption states that the breaking of Enigma shortened the war by two years. This should read “the work of Bletchley Park shortened the war by two years”. Many ciphers were broken and especially the Lorenz breaks made massive contributions to the war effort. It’s not fair or balanced to omit this achievements.

Did Alan Turing commit suicide?

The coroner said yes although its never been conclusively proven that Turing’s death was suicide. Although there’s no doubt that cyanide caused his death, it use was a constant part of his work and it was commonly present in his home. Contrary to popular belief, the apple by his bedside was never tested for cyanide, so the story that he injected the apple is not true, or at least not proven. Sadly, it is very likely he did take his own life but we’ll probably never know for sure.

The Imitation Game is still played today

Turing’s thought experiment, ‘The Imitation Game’ states that if you cannot tell whether an intelligence is artificial then what is the difference? Can it truly be described as artificial? This is still the gold standard for artificial intelligence research today. Every year, the Loebner Prize is awarded to the most convincing ‘chatbot’ that has a conversation with a judge who is unaware whether their opposite number is a human being or a computer. A chatbot has never won the game, but they have come surprisingly close. I should know, I was a participant in the 2012 prize, which was held in Bletchley Park to celebrate Turing’s 100th anniversary.

The classified nature of Bletchley Park, and the lack of reliable evidence surrounding its operations makes any research a frustrating affair. Everything I have stated here is correct to the best of my knowledge but if you know differently, please drop me an email and I’ll be happy to make improvements.

Further Reading