by Jim Eldridge
Frustrated, Alan and Gordon Welchman, along with fellow code-breakers Hugh Alexander (who was also the British chess champion) and Stuart Milner-Barry, decided to take matters into their own hands. They wrote a personal letter to the Prime Minister, Winston Churchill, appealing for the skilled workers needed:
Dear Prime Minister
Some weeks ago you paid us the honour of a visit, and we believe you regard our work as important. You will have seen that we have been well supplied with the Bombes for the breaking of the German Enigma code. 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.
This personal appeal to Churchill had an immediate effect. Churchill is on record as saying that preventing the German U-boats destroying the North Atlantic convoys was the single most important element of the Second World War, adding: ‘The only thing that ever really frightened me during the war was the U-boat peril.’ He knew it was vital that everything must be done to break the Naval Enigma code, and he issued his own memo to the War Office, attached to this letter. It said:
Action This Day. Make sure they [Bletchley Park] have all they want on extreme priority and report to me that this has been done.
Gradually, with more staff identifying the cribs and running them through the Bombes, the Enigma code began to be broken. However, the cracking of the code led to another problem: If the military took action based on the cracked messages, then it could arouse the suspicions of the Germans that their code had been broken, and they might well change the code structure again.
For example, the code-breakers at Bletchley were able to locate the positions of some German supply ships by breaking the coded messages sent to and from the ships. The RAF sent bombers to that location and attacked and sank those ships. Fortunately for the Allies, the Germans felt so secure that the Enigma code was unbreakable that they blamed the successful attack on their ships on espionage, assuming that secret agents must have passed the information about the location of their ships to the Allies.
However, the Germans would not remain so confident if more ships were sunk. So the Allies had to be careful not to use all the information they got from cracking the German wireless messages, in order not to alert the Germans to their success. They used subtle means: if they had discovered the location of a wolf pack of U-boats in the Atlantic from Enigma, they would then arrange for the RAF to fly over that location, as if on a general reconnaissance mission. The attack on the U-boats would then be put down to the U-boats having been spotted by those planes.
At the same time as Alan and his team were breaking the German navy’s Enigma code, another team at Bletchley was working on breaking a code known as Tunny, which was used by the German army in Europe. The work this team, especially the cryptoanalayst Bill Tutte, did in breaking Tunny is held by many to be equal to the work carried out by Alan and his team on cracking Enigma. If Tunny could be decoded, the secret transmissions between Hitler’s commanders across Europe could be read, and the actions of his army prepared for. Once Bill Tutte cracked Tunny early in 1942, a new team was set up to continue the work of decoding the Tunny messages. This team was led by Ralph Tester. He, like most of the new Tunny team, came from Alan’s unit at Hut 8, and used the techniques and code-breaking skills they had learnt while working under Alan.
* * *
Alan’s time at Bletchley also brought him a new relationship – for the first time, with a woman.
Up until he joined Bletchley, Alan had been in mainly all-male establishments. Hazelhurst and Sherborne were both boys-only schools, and the Maths Department at Cambridge had been very much a male enclave. At Bletchley Park, however, although all the senior boffins were men, a large number of women were employed there: some were WRENS (from the Women’s Royal Naval Service), and there were also women, many of them from Oxford and Cambridge, who operated the Bombes, and carried out most of the transcription and translating work.
One of the women on Alan’s team in Hut 8 was a mathematician called Joan Clarke. For the first time in his adult life, the shy and lonely Alan found he could talk to a woman in an easy manner, without stammering and stumbling over his words. Whether he began to improve his dress sense and stop keeping his trousers up with string at this time is not known, but one thing is sure: Alan and Joan began a relationship.
The fact that she was a mathematician helped enormously, but their friendship was about more than just numbers and calculations; on their days off the two would often go to the cinema, and also go for long bike rides together. As their friendship deepened, Alan asked Joan to marry him, and she agreed. However, once they were engaged, Alan knew he was being unfair to her in not being honest about his sexual nature, and so he admitted to her that he had ‘homosexual tendencies’, that he was physically attracted to men rather than to women. Possibly to his surprise, Joan told Alan that she was prepared to accept this side of him, and they agreed to get married once the war was over. In the meantime, there was important work to be done.
8
Alan Returns to America
In December 1941, Japanese fighter planes bombed the US Naval base at Pearl Harbour in Hawaii, bringing America into the war.
Now, with America as a legitimate enemy (previously it had been neutral), the Germans began to launch attacks by their U-boat wolf-packs on American ships, and especially on American ships close to America’s east coast.
America had never been under attack by submarines before, and as their losses mounted, they realised they needed the help of experienced people if they were to properly defend against the German U-boats. They needed someone who could help them unscramble the coded messages sent to and from the U-boat fleets that lurked off their coast and attacked their ships in the Atlantic. They needed an expert who could help them break the constantly changing Enigma code.
They needed Alan Turing.
In November 1942, Alan was sent by the British by sea to New York. Fortunately, the ship he was on arrived safely, avoiding attacks by German U-boats on its journey across the Atlantic. Alan was immediately sent to the American capital, Washington DC, where the American code-breaking team was based. Alan briefed them on how he and his fellow scientists at Bletchley Park had cracked the Enigma code, but warned them that, as the main codes were altered all the time, attempts at keeping up with the German code had to be constantly updated. If they were going to keep breaking the ever-changing Enigma code, they needed to build Bombes capable of the work.
The Americans, a far richer nation than Britain, responded immediately. Unlike the conditions at Bletchley Park, where money and resources seemed always stretched and barely adequate, the code-breaking system in America swung into action. A factory in Ohio that had produced cash registers for NCR (the National Cash Register company) began building Bombes for the US Navy to Alan’s designs.
The American Bombes were much faster than the British Bombes at Bletchley. One reason was that the drums used in the American machines to drive the rotors rotated at 1,725rpm, which was 34 times faster than the British Bombes.
In the same way that at Bletchley responsibility for decoding messages sent by the Germans was split into Navy (Hut 8 under Alan) and Army and Air Force (Hut 6 under Gordon Welchman), the Americans split their code-breakers into Navy and Army. The Bombe designed for the US Army, although based on Alan’s work, was built by Bell Labs and very different from that used by the US Navy. Instead of using rotating drums to represent the Enigma rotors, the Bell Labs version used telephone-style relays. This meant that changing the order of rotors could be done electronically in about half a minute, simply by pushing a button, whereas changing the drum mechanically took about ten minutes.
As well as working with the American
cryptographers on cracking Enigma, Alan took advantage of his time in America to investigate other scientific advances that were going on there. He was excited at the work being done at Bell Labs as they attempted to encrypt actual speech. If that could be done, then it would be possible to send secret voice messages, rather than having to send everything in Morse code, or written codes.
Alan also met Claude Shannon, a pioneer of computer science who was based at the prestigious Massachusetts Institute of Technology (MIT). The pair discussed whether a machine could be built that could imitate the action of the human brain. Alan had always believed it was possible to design and make a thinking machine, one that worked on the same logical processes as human thought. Shannon’s ideas went even further: he talked about machines being able to read and understand poetry, and listen to and appreciate music.
His meetings in America with Claude Shannon and the scientists at Bell Labs set Alan in a new direction in creating his Thinking Machine, one that would have a major impact on the future of the world.
It was during his visit to Bell Labs that Alan came out with one of his most memorable remarks. While addressing the executives at Bell about his ambition to create a machine that could think, he said: ‘I’m not interested in developing a powerful brain. All I’m after is just a mediocre brain, something like the President of the American Telephone and Telegraph Company.’
This was the company that owned half of Bell Labs. The executives weren’t sure whether this was a joke, or an insult, and Alan didn’t clarify.
9
Return to Britain
In March 1943, Alan returned to Britain on a troopship. Again, he was lucky it wasn’t a target for German U-boats. Possibly he trusted in the fact that by now his colleagues in Hut 8 at Bletchley Park, thanks to the cracking of the Enigma code, had German U-boat movements in the Atlantic under some sort of control.
In his absence, Hugh Alexander, Alan’s code-breaking colleague and one of the co-signatories of the letter to Churchill, had taken over the leadership of Hut 8, continuing the work of code-breaking the German naval Enigma. As Alan soon realised, the code-breaking work of Hut 8 was proceeding well, with the Enigma codes being broken and the German’s secret messages being read successfully and regularly. To a great extent, Alan was no longer vital to the work of Hut 8.
The commanders at Bletchley Park offered Alan a new code-breaking challenge instead. The Germans were using another code, this one produced by the German Lorenz machine, which the British called Fish. (Tunny was one of the codes produced by this system.) To break this code, a team had designed and built an electronic machine, which they called Heath Robinson, which used two paper tapes. The first tape had on it coded characters from an intercepted message; the other tape had possible wheel patterns from the Lorenz code machine. The paper tape ran through the machine at a thousand characters a second. The main problems with this machine were that the paper tapes often got out of sync, and that the paper often snapped.
Max Newman, one of Alan’s former tutors at Cambridge, had looked at the problems affecting the Heath Robinson machine, and he and an electronics engineer called Tommy Flowers had designed and built their own version of the machine, which used patterns generated electronically rather than paper tape. Because of this it was able to process five thousand characters a second. Newman and Flowers called their machine Colossus. It was one of the very first digital electronic computers. Newman invited Alan to join him and Flowers to develop Colossus and give it even greater ability.
Alan declined. The research he had been exposed to in America, particularly the voice encryption work at Bell Labs, inspired him to want to develop a machine that not only had the power of independent thought and decision-making – his Thinking Machine – but one that would be able to communicate using speech. If this could be done and the coded message could be simply listened to as real human speech, then the long job of translating a physical code, letter by letter, as had previously been the case, would be unnecessary.
* * *
Meanwhile, what of Joan Clarke? When Alan had left for America the previous November, there was an understanding between them that they were engaged, and would be married. But perhaps their time apart had given them both time to think about what such a marriage might mean for them, especially in view of Alan’s admission to being gay. When they met again on his return to Bletchley, Alan expressed his doubts that a marriage between them would be successful in view of his homosexuality. Joan took his decision with understanding, and the two promised one another they would still be friends. But from that time on, their friendship would never be as deep and close as it had once been.
By all accounts, the ending of his engagement to Joan had little emotional impact on Alan. Possibly theirs had been the kind of ‘romance’, however ambiguous in its nature, that was kindled during the intensity of war, but once time passed Joan became just another friend in Alan’s eyes, and then an acquaintance. Ever since the death of Christopher Morcom, Alan had not really shown any inclination to get deeply emotionally involved with anyone.
Was Alan lonely at this time? Possibly, but he never expressed any feelings of loneliness in his writings, or to his colleagues. To all intents and purposes, Alan’s life was poured into his work. He did not appear to need other people.
10
Delilah
After turning down the opportunity to work with Max Newman and Tommy Flowers on their prototype computer Colossus, Alan left Bletchley Park and moved to another Special Operations unit at Hanslope Park, just ten miles away from Bletchley. Like Bletchley Park, Hanslope Park was another country estate with a large historic mansion house. Since 1941 it had been the base for Special Communications Unit Number 3, which researched ways of sending and receiving coded messages.
Inspired by the work he had seen at Bell Labs in America, Alan was determined to create a secure method of communication that used encrypted human speech. Alan’s plan was to create and build a machine that could turn human speech into an encrypted form that sounded like static, using a machine called a Vocoder. This ‘static’ would be unintelligible to anyone listening to it; but when that sound was played through a translator at the receiving end, it would be turned back into intelligible speech.
This was very different from just turning a message into a sound code, such as Morse, where a short bleep (a dot) or a long bleep (a dash) represented a certain letter in the alphabet. Human voices are made up of a mix of sound waves. This means they are analogue, not digital. So first a system had to be worked out to transform this analogue sound into a digital state.
Although this does not sound such a difficult proposition in this digital age, in 1943 electronic engineering was still in its early stages, and the process of finding a way to encrypt human speech would take many months of experiments.
Alan was given two young assistants to help him with his work: Robin Gandy, a mathematician, seven years younger than Alan, and Donald Bayley, an electrical engineer who had just graduated from University. It was Robin Gandy who came up with the name for their project: Delilah.
Finally, in March 1944, Alan and his small team succeeded. They were able to encrypt a recording of a speech made by Winston Churchill, send it as ‘static’, and then decode it back into its original form.
However, it would take almost a year before Delilah would be fully operational. First the team had to iron out small technical problems with the sound system, to make the sound at the receiver less crackly. By the time Delilah became fully operational, in the spring of 1945, the Second World War was about to end. But all the work that had gone into creating Delilah had not been wasted; it had set the stage for future generations of machines that could communicate using human speech.
11
The Modern Computer Age Begins
On 7 May 1945, Germany surrendered. The War in Europe was over.
In June 1945, Alan was awarded the OBE (the Order of the British Empire) for his services to code-break
ing and code-creation during the War. It was generally accepted that his work in cracking the Germans’ Enigma code, in particular, had brought about the defeat of Germany much sooner than otherwise would have been the case.
Because of the clandestine nature of his work, the OBE was awarded to Alan in secret, and neither he nor the others at Bletchley Park or Hanslope Park were allowed to say anything about the work they had carried out during the war. By all accounts, this lack of publicity about being awarded the OBE didn’t bother Alan in the slightest. According to people who knew him, he simply put the medal in a drawer and then forgot about it. Public accolades and awards didn’t interest him: his ambition lay in breaking new boundaries in his work.
However, the secrecy of the work they carried out at Bletchley Park had been a source of embarrassment for many of the young men who worked there during the war. Because the work that was going on at Bletchley had been kept under wraps, many of the people who lived in the towns and villages around the place had developed their own theories about what was going on. A lot of them decided that, although Bletchley Park was officially some sort of Government establishment, it must be some sort of rest home for privileged young men who didn’t want to fight in the war. As a result, many of the locals considered the young men to be cowards, hiding away from the action, and treated them as such when they encountered them in the local villages. Other locals, however, began to suspect that something was going on at Bletchley Park, once they realised that most of the young men there were mathematicians, chess masters and puzzle solvers.
When the war ended, Alan had decisions to make about his future. One option was for him to return to Cambridge University and become an academic, occasionally lecturing, but mainly conducting mathematical research.