Read The Secret Life of Bletchley Park Online
Authors: Sinclair McKay
Bletchley Park seemed an organic kind of institution. Perhaps, given the early, experimental nature of the work â so many minds attacking the problem of the codes in so many ways â there was little point in trying to give it an over-rigid structure. Nevertheless, in contrast to strict naval and military hierarchy, the place from the start seemed curiously self-disciplined. âThere were an awful lot of people who just used first names,' recalled one veteran, surprisingly given how socially formal the period was.
Meanwhile, Alistair Denniston's administrative difficulties were growing. There were problems involving accommodation for all the staff. An adjacent school â Elmers School â had to be requisitioned as more huts underwent construction.
Looking at these old huts now, one cannot help wondering why the authorities did not base the codebreaking activity in rather more comfortable, better-built space. One possible answer is that at that stage, no one anticipated the war lasting long enough for permanent structures to be needed. After all, even up until the summer of 1939, there were many who believed that Chamberlain's government would, of necessity, allow Hitler to get away with further acts of aggression throughout Europe. Perhaps another consideration was that it was vital that no unfriendly attention was drawn to the Park. Not only would extensive building work raise questions, it would also be more easily visible from the air by enemy reconnaissance pilots.
And so a series of huts were constructed and accorded separate functions, decided by the sorts of codes that were to be read. By the side of the house was Hut 4, which was to become the Naval Section hut. Hut 5 was to become the Military (and later, the Japanese) Section. Other huts, such as Hut 8, the home of the Naval Enigma operation, followed not too long afterwards.
Hut 3 â which, together with Hut 6, seemed to form the hub of the operation â was nominated in part for army/air intercepts and Intelligence work; Hut 6 was where air force keys were to be read. Hut 1 eventually came to house the first experimental Turing bombe deciphering machine. (And according to Mimi Gallilee, âHut 2 was for beer, tea and relaxation.')
From the very start, for the sake of security, the functions of each hut were kept as separate from each other as possible. Personnel were instructed that inter-hut discussions were forbidden. Absolute secrecy was a given. âYou just assumed,' says Keith Batey drily, âthat you'd be shot.' Recruits would be allocated to their hut and, during working hours, would be metaphorically hermetically sealed within. No one else, save the occasional messenger, would be allowed entry.
Even though the word âhut' implies a cramped construction, these were long structures, with central passageways and rooms off either side. There were plain windows (shuttered at night for blackout
purposes), floors of squeaky lino, basic desks and chairs. Green-shaded lights hung from the ceiling. A great many people worked side by side among plain filing cabinets; the rooms were suffocating in the summer sun, and draughty and cold in the depths of winter. As one cryptologist commented: âNothing ⦠seemed less likely to house great matters than the ramshackle wooden building (its atmosphere nauseating at night when the blackout imprisoned the fumes from leaky coke-burning stoves) to which I reported â¦'
Heating was a perennial problem. Mittens were commonplace. Added to this was a faintly comical, Heath Robinson dimension: messages were passed between some huts by means of an extemporised wooden âtunnel' and propelled by means of a tray with wheels on the bottom, and a long broom-handle.
John Herivel recalled the unique atmosphere in the ill-ventilated and sporadically heated huts. There were the big tables, covered with maps. Then there were the spartan lights giving out yellowish light on the simple desks and the bare whitewashed walls. Mr Herivel recalls that he was âprovided with a blackboard set on a low table' so that he could write while seated. And before him was a desk piled with intercepted messages.
The phrase âneed to know' was constantly evoked. Even for the young messenger girl, Mimi Gallilee, moving from hut to hut delivering the post and packages, entry was sometimes forbidden. Even though her older sister worked in Hut 10 alongside Josh Cooper, Mrs Gallilee recalls: âI never knew what my sister did in Hut 10. I never even asked her. She wouldn't have told me anyway. She knew where I worked. Later, when I was promoted and moved into office work at the house, she never came to my department. I had to go to Hut 10 on a few occasions for my own department. I'd be asked to go over to Commander This or Squadron Leader That in Hut 10 and I'd see my sister sometimes.
âOn the few occasions when I had to go over to her Hut, to talk to someone â if it was in the room she was working, I can remember
seeing pieces of paper â not slips of paper but sets of figures. And so my sister would have been working on figures or letters, I don't know which.'
As the work of the Park continued to expand, so too did the demands for space. The Secret Intelligence Service had now, briefly, evacuated to Bletchley. They were occupying the upper floors of the house, though thanks not only to issues of space but also to straightforward operational concerns, they did not stay long. Meanwhile, in the early days, the ground floor played host to GC&CS, with the numbers growing daily. The corridors of the house were full of trestle tables. The telephone exchange was in the ballroom. The Naval Section, for a while, had to find a temporary home in the library.
For Dilly Knox, Alan Turing and Gordon Welchman, sanctuary was found in the Cottage. By this time, Turing, then just turned twenty-eight, was already at work on the design of his revolutionary âbombe' machine.
In these first few months, the irascible Dilly Knox was beginning to take stock of the people that he had gathered around him. In a handwritten letter to Denniston, he reported of his young underlings: âAs you know, Joan H is a great personal friend of my family and myself. But as a secretary, she is frankly a flop.' Knox then gave his bullet-pointed appraisals of the others:
A few notes on senior staff:
a) Kendrick is quite admirable. It is a pity I have put him in the [Elmers] school since, tho' he has a lot to learn, he is the obvious second (or first?) in command.
b) Welchman is doing well and is v keen. I hope to get him back here [from Elmers School] to learn about the machines.
c) Twinn is still very keen and not afraid of work.
Knox's attitude towards the young Alan Turing was more ambivalent:
He is very difficult to anchor down.
He is very clever but quite irresponsible and throws out a mass of suggestions of all degrees of merit. I have just, but only just, enough authority and ability to keep him and his ideas in some sort of order and discipline. But he is very nice about it all.
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For a little while, there was some tension between Dilly Knox and Gordon Welchman. Knox as the senior cryptographer felt that the Cottage was overcrowded. So Welchman was exiled to the nearby temporarily requisitioned Elmers School (as the memo cited above indicates, Knox was keen that the exile should be short). The idea was that, rather than codebreaking, Welchman would be trying to crack the slightly different problem of âtraffic analysis'. This involved studying the origins of intercepted signals to work out where they came from, and thereby hopefully making deductions about military movements.
Welchman wrongly inferred from his exile that Knox had taken a dislike to him; as a result, he seemed to suffer slightly from wounded pride. It also seems to be the case that Welchman wasn't smitten by Knox himself. Years later, he wrote: âHe was neither an organisation man nor a technical man. He was, essentially, an idea-struck man ⦠By and large Dilly seems to have disliked most of the men with whom he came into contact.'
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Knox might well have smelled something to his distaste about the younger man; for very early on, Welchman was working on schemes to restructure and reorganise the entire codebreaking operation, in such a way that a great deal of power and authority would have slipped from Knox's hands.
Indeed, Welchman wasted no time at all during his exile. Mathematician John Herivel recalls one of the key innovations. Welchman was quick to form a strong working relationship with the most secret listening station â âan old fort' at Chatham, Kent, on the Thames Estuary. It was through this establishment that, at that time, much of the German signalling traffic came.
Once the signals were picked up, the officers at Chatham would have bundles of intercepted coded messages sent to Welchman. These bundles would be driven from the coast to Bletchley, through the middle of the night and at harum-scarum speeds, often in the most atrocious weather conditions, by special motorcycle couriers.
The German rule was that no message should be more than 250 letters in length; if it was necessary to send a longer message, it should be split into multiple parts. This was designed to make life more difficult for codebreakers: the longer the message, the easier it might be for such a person to see patterns of letters forming among the apparent chaos.
But each Enigma message had a preamble and some operators used different discriminants (that is, groups of characters indicating the code set-up and reciphering key, and distinguishing the section of traffic) for the different parts. As Herivel noted, it was thus possible to work out any âgiven key'. âIn this way,' he wrote, âall the different German keys coming from Chatham â and later from France â could be identified, and every day, traffic could be divided into different bundles for different keys.'
The keys were then given different colours, to separate them out in the most direct visual way. To start with, the colours used were yellow, green, red and blue, respectively signifying the German Norway campaign, the army and air force codes, and separate air force training codes. The time and the frequency of each message would be noted down on vast sheets of paper, leading to an immediate strain on the Park's supply of coloured pencils. But the colour keys were a stroke of organisational genius â a vivid signifier that allowed everyone to identify each key with ease. Indeed, Welchman recalled in his memoir that one element of recruitment to Bletchley Park involved asking candidates âif they were colour-blind'.
In our world of ubiquitous touch-screen technology, such a system smells of pencil shavings and glue and bits of string. But it worked. The avalanche of thousands upon thousands of intercepts â the numbers of which would multiply dramatically as the Phoney
War ended and the conflict intensified â had order imposed upon it. It could be deduced from which part of the German military they were being sent, and to which.
It soon became necessary to develop subdivisions for the keys (such as SS messages, and messages to do with German railways); before long every colour in the rainbow was deployed. When all available colours had been used, keys were named after marine life: birds; then elephants; and insects â¦
There were many occasions when a message could not be broken in its entirety, because words were missing or incomplete. As a result, a comment would be added with the words âstrong indications', âfair indications' or âslight indications' to convey the varying degrees of the decrypt's reliability. But it was through the work of Chatham â and later other intercept stations such as Denmark Hill in south London â that Welchman began to understand about the different call-signs used by different operators, and what signs would be used for what sorts of messages.
Dilly Knox was also using the period of the Phoney War to get himself and his team ready for the onslaught of work that was to come. The difference between Knox and Welchman was Knox's apparent taste for pulchritude on his team, although now Mavis Batey laughs off â with a very faint edge of annoyance â any idea that she was recruited chiefly for reasons of glamour: âDilly was very firm. He said he did not want any debutantes who had got there by Daddy's knowing someone in the Foreign Office. Equally, he said, he didn't want a yard of Wrens who all looked alike and you couldn't tell one from the other.
âAs for Dilly going around picking out girls, that is totally untrue. We were all interviewed by this dreadful Miss Moore, a fierce lady in the Foreign Office.'
There is another possibility too; that Dillwyn Knox had somehow found that women had a greater aptitude for the work required â as well as nimbleness of mind and capacity for lateral thought, they possessed a care and attention to detail that many men might not
have had. This, of course, is just speculation; the other possibility, and one that seems likely considering the scratchiness of many of Knox's personal dealings, was that he simply did not like men very much.
As the war effort intensified, new recruits would be given a statutory three-week induction period to be taught the nuances of code-breaking. Later still, recruits were sent to Bedford for a few weeks, to sit in a dusty, anonymous office where they learnt the rudiments of Japanese, in order to be able to crack the Japanese codes.
But for that first wave of recruits, Bletchley Park as an institution had what some have described as a peculiarly English air of improvisation, of simply diving in and getting on with it. Perhaps there was no other way. For in the face of a challenge like the Enigma keys and without, at least at first, the technology to be able to attack them mechanically, the Park would need as many original, quirky, lateral thinkers as it could get, and then give them as free a rein as possible. This created a unique atmosphere that was to be remembered, despite the nature of the conflict in which they were so deeply involved, with the utmost fondness by everyone who served there, even if they were not allowed â under the strictest oaths of secrecy â to discuss even the smallest detail of it for decades afterwards.