Gordon Welchman Read online

  Given Knox’s temperament it is likely that he occupied himself with two problems at once; determining the machine’s wiring connections, and analysis of the message keys. This might have been the real cause that he did not progress satisfactorily on either problem. His secretive nature certainly did not help any.

  Chapter 3

  The Ultra Architect

  As students drifted back to Cambridge for the start of the 1939/40 academic year, a certain lecturer in algebraic geometry was conspicuous by his absence. The rumour making the rounds of the common room at Sidney Sussex College was that he was doing important war work of a secret nature. A number of students he had been supervising before the war began would be seeing him again soon enough. While secrecy was paramount at BP, it would seem that not everyone was in total ignorance of the activities taking place there.

  Diana Neil, who worked in Hut 4 from March 1944 to December 1946, was from Bristol and Welchman’s father had married her parents during the First World War. When he and his wife had moved to Bristol and he became an archdeacon, Diana and her family attended his church. As she later recalled:

  Mrs Welchman had died in 1938, the church was burned down by incendiary bombs in 1940 and the Archdeacon went to live with his brother in Bradford on Avon. One day I thought I would go and visit the dear old gentleman when I was on leave. I duly did in my Wren uniform, and was invited to stay for tea. During tea he asked, ‘Now my dear, where are you billeted in the WRENs?’ I replied how fortunate I was to be living at Woburn Abby. ‘Really my dear,’ he said. ‘And where do you work?’ I hesitated but then thought this dear old man would never know in any case, so told him I worked at a small place nearby called Bletchley. ‘Do you mean Bletchley Park my dear?’ Oh, my goodness what have I said, so had to admit it was. So he said: ‘My son Gordon, who had a First Class Honours Degree in Mathematics at Cambridge, he’s working at Bletchley Park, on very secret and important government business.’1

  *

  Just before the beginning of the Second World War, the Polish cryptanalysts had shown the British and French how the Enigma traffic of the German Army and Air Force could be broken by a manual method involving large numbers of perforated sheets. In September 1939, a great deal of this Enigma traffic was being intercepted, but it was not being properly analysed by GC&CS, now based at BP. After being assigned to the neglected task of traffic analysis by Dilly Knox, Welchman soon realized that BP was almost certainly going to be able to break a great deal of this traffic. To exploit such a great opportunity, they were going to need the co-ordinated efforts of several specialized organizations, including the radio intercept stations and he had already established close contact with one of these stations. BP was faced with an unprecedented situation, quite different from the one that cryptanalysts had encountered in the First World War, when messages were broken one by one. If they could discover the key which told German Enigma operators how to set up their machines on a particular communications network, they would be able to decrypt all messages using the same key. The Germans were already using several keys which were valid for twenty-four hours and even in the summer of 1939, before Germany invaded Poland on 1 September, the British intercept stations were intercepting hundreds of messages each day. As Welchman remembered in The Hut Six Story:

  Previously I suppose I had absorbed the common view that Cryptanalysis was a matter of dealing with individual messages, of solving intricate puzzles and of working in a secluded back room, with little contact with the outside world. As I studied the first collection of decodes, however, I began to see, somewhat dimly, that I was involved in something very different. We were dealing with an entire communications system that would serve the needs of the German ground and air forces. The call signs came alive as representing elements of those forces, whose commanders at various echelons would have to send messages to each other. The use of different keys for different purposes, which was known to be the reason for the discriminants, suggested different command structures for the various aspects of military operations.

  Even more important perhaps, was the impression I got from the messages themselves. Although my knowledge of German was very limited, I could see that the people involved were talking to each other in a highly disciplined manner. They were very polite to each other, in that the originator of the message would be careful to give the full title of the officer or organization to which the message was to be sent. Furthermore, in the signature that came at the end of the message, the originator would be careful to give his own title in full. These early impressions proved to be of immense importance later on, and it was fortunate that I had this period of secluded work.

  As no one at BP seemed to have recognized that intercepted German messages represented a potential intelligence gold mine if the traffic as a whole were analysed, Welchman drew up a comprehensive plan. He called for the close co-ordination of radio interception, analysis of the intercepted traffic, breaking Enigma keys, decrypting messages on the broken keys, and extracting intelligence from the decrypts. He presented the plan to Deputy Director Edward Travis, who immediately saw the urgent need to act on it.

  Having convinced Travis that a large scaling-up of the effort would be needed when these methods of breaking Enigma produced results, he sketched out what a room containing codebreaking machinery and British-built Enigma machines might look like. He also foresaw that processes akin to mass production would be required. The codebreaking procedures that he had been introduced to in March were ones in which the various tasks of decryption, translation, and writing the resulting out-going message were all performed, essentially, by one cryptanalyst. He had realized that this approach would simply not scale to handle the volumes of intercepted traffic envisaged. It would have to be replaced by a clear division of labour amongst a team of experts. Remarkably, Travis persuaded Whitehall to back this gamble, even though at that stage not one German Enigma message had ever been broken in the UK either before or since the war began.

  It is not surprising that Welchman decided not to discuss his ideas with Knox, given that he had felt excluded from Knox’s team in The Cottage. However, it is surprising that he chose to approach Travis rather than Alastair Denniston, the Director of GC&CS and that Travis in turn bypassed Denniston and went straight to Stewart Menzies, head of MI 6. There is some evidence that Denniston was away from BP at the time due to ill health. Travis may also have been concerned that Denniston and Knox had been together in Room 40 in the Admiralty during the First World War, and had become close friends. Travis had joined the Royal Navy in 1906 and worked on the security of Royal Navy ciphers, and on liaison on such matters with the Navy’s allies in France and Italy beginning in 1916. It is likely that he had little contact with the codebreakers in Room 40. They had come together in 1919 in the newly formed GC&CS, with Denniston taking responsibility for cipher-breaking, and Travis for cipher security under him. This separation of roles had continued in the early days at BP, even though the cipher ‘Construction Section’ was now based in Oxford. Travis had been made responsible for the service sections of GC&CS in 1938. Denniston’s management style did not include spending much time out of his office and in effect ‘visiting the troops’. In any event, he was very busy coping with the administrative problems arising from the move to Bletchley and the subsequent expansion. But Travis did make it a habit to get out, seeing the work on the ground and talking to the staff. So it seems that Travis was made responsible for the ‘Enigma Section’, though Dilly often continued to write straight to Denniston. Travis would have had a direct interest in the security of Enigma as at this time he was concerned with the deployment in the British services of the Typex machine, which was designed on very similar lines. On 18 November 1939 Denniston received an unsigned memo, proposing that, once they were in a position to decrypt traffic:

  I should like to see Research divorced from Production and the work organized on the following lines:-

  Research Section who should investiga
te the still unknown problems such as the Naval and T.C.D. [Gestapo Enigma?] This should be done by Knox, Kendrick, Turing, Miss Nugent, and such of the clerks as Knox requires.

  The production section requires dividing into several subsections as follows:-

  i)

  Receiving, sorting and W/T Liaison. This section would prepare data for Netz and Bombes. Staff: Welchman, Twinn and 4 clerks.

  ii)

  ‘Netz’ party. The work of finding machine settings etc., from sheets punched from cyclometer results, Jeffries [sic] + X assistants.

  iii)

  ‘Bombes’ machines run by Dawson + 1 assistant.

  iv)

  Decyphering Section. This should include staff to test ‘Netz’ and ‘Bombes’ results. They will decipher all available traffic with minimum loss of time and pass to Service Sections for translation. It will require someone (or ones) with good German to scrutinise traffic before passing on for translation. Two female typists must be trained by R.A.F. to work their machines.

  A special hut will be required for the Production section.2

  While no copy of Welchman’s original proposal to Travis seems to have survived, from his account in The Hut Six Story, this memo was clearly based on it. Welchman would say later in life that his proposal to Travis was probably his greatest contribution to the war effort and many historians would agree with him. The memo itself was certainly not written by Welchman as he would never have proposed himself for any specific role. At the top right of the front page of the memo are the words ‘Paper? By EWT.’ It seems highly unlikely that Travis would have used the words ‘I should like to see’ to his superior. However, he may well have gone above Denniston’s head to his superior, Menzies, and felt empowered to write this memo.

  The Welchman proposal was for an organization which would remain basically unchanged throughout the war, with the hut numbers becoming, in effect, the cover name for their activities. Army/Air Force codebreaking and intelligence would be based in Huts 6 and 3 respectively. Their Navy counterparts would be in Huts 8 and 4.

  Denniston and Travis were quite different in personality and management style. While Denniston allowed creativity and innovation to flourish in the early days at BP, Travis proved to be the ideal person to fight the battle in Whitehall to get authority for the resources that would be needed for the expansion. It is unlikely that Denniston, for all of his qualities and huge personal contribution to the ultimate success of BP, would have been as successful in Whitehall. Subsequently, Travis continued to take direct responsibility for the Enigma huts as they came on stream, their staff, and the mechanization programme. Denniston remained ‘in charge’ as Operational Director of GC&CS.

  Recruitment of the high-quality staff that would be needed started almost immediately and the future Hut 6 was Welchman’s priority. The emergency list of ‘men of the professor type’ that had been drawn up the year before had been quickly exhausted and a new intake was needed as soon as possible. The men who would form the first management team of Hut 6 came from a number of places but not surprisingly, much as Birch and Adcock had done before him, Welchman returned to the fertile recruiting grounds of the Cambridge colleges.

  The first two recruits to Hut 6 were in Argentina at the outbreak of war representing the British chess team in the Olympiad. Stuart Milner-Barry had come up to Trinity College, Cambridge, in the same term (October 1925) as Welchman and they had been friends ever since. Milner-Barry had studied classics. He had entered the world of stockbroking when he had the call from Welchman to join him at BP.3 He duly recruited his friend and fellow chess player C. H. O’D. (Hugh) Alexander, a scholar of King’s College and a mathematician. He was working as Director of Research at the John Lewis Partnership and while that was not an ideal role for him, his management experience there would prove to be valuable in the years ahead. Following a year in Hut 6, he joined the newly opened Hut 8, where he would remain for the rest of the war. Following their arrival at BP in January 1940, Milner-Barry and Alexander were billeted at the Shoulder of Mutton inn about one mile from BP. Writing years later, Milner-Barry had fond memories of the hospitality of the inn-keeper, Mrs Bowden, and he and Alexander would remain there until they left BP at the end of the war. Welchman lived with them for a while but soon moved out to live with his wife in a nearby town.

  Welchman admitted after the war that he shamelessly recruited former friends and students, and before long he was back in Cambridge. He appeared one evening at the door of one such student. John Herivel and his friend Malcolm Chamberlain had been supervised by Welchman for six terms. Now here he was in Herivel’s rooms, asking him for help with secret war work that he was doing at a place called Bletchley. Bored with the ghostly atmosphere of Cambridge at that time, Herivel agreed and duly arrived at BP on 29 January 1940. Chamberlain joined them around the same time. They found that another of Welchman’s students, David Rees, was already there, having arrived in December 1939. Rees was a brilliant mathematician and would become one of Welchman’s ‘wizards’ in Hut 6. Non-mathematicians were also recruited from Sidney Sussex, including Howard Smith and Asa Briggs who arrived in 1939 and 1942 respectively. Welchman was helped in his recruiting drive by John Jeffreys, a former Research Fellow at Downing College, fellow maths supervisor and close friend. Jeffreys had arrived at BP about the same time as Welchman and had been on Denniston’s emergency list of ‘men of the professor type’.

  Another former colleague on the same list eventually arrived at BP at the end of 1939, but not without some difficulty. Dennis Babbage was a fellow geometer and friend from Magdalene College, Cambridge. He had attended the same pre-war sessions between Cambridge’s Lent and Easter terms in 1939 as Welchman and, like him, was told that he would be summoned in the event of war, which they felt was inevitable. He had heard nothing after the declaration of war on 3 September and in frustration made contact himself. He had heard rumours that there were limits on numbers at BP, but eventually Tiltman ‘smuggled’ him into BP as a soldier of sorts. He spent some time in The Cottage with Knox’s team in January 1940 but learned very little from him before he moved to Hut 6 to become another of Welchman’s ‘wizards’.

  Two other friends from Cambridge would also arrive in Hut 6 in due course, Harold Fletcher in August 1941 and Houston Wallace in March 1942. Fletcher was working in a reserved occupation when he was recruited by Welchman. After overcoming the difficulties of being released so that he could be placed on the special reserve and employed for wartime duties by the Foreign Office, he duly arrived at BP.

  Welchman even went back to his old school, Marlborough College, looking for recruits and asked his old mathematics teacher there, A. Robson, to send him his best young mathematicians. This produced another group of excellent people, including John Manisty, who arrived in 1941. The old boy network would yield other recruits to Welchman’s team including Alex Aitken, the Scottish chess champion, and David Gaunt, a classics scholar from Cheltenham College. Even Travis got into the recruiting game, producing two scientists in early 1940, John Colman and George Crawford, who had been a former schoolmate of Welchman’s at Marlborough. Travis also persuaded some of the London banks to send him bright young men to handle the continuous interchange of information that he envisaged would take place between Hut 6 and the intercept stations. Through this route and other personal contacts came Reg Parker, Frederick Braithwaite, Edward Smith and later John Monroe.

  Then there were the young women who would prove to be vital cogs in the Hut 6 organization. The first recruit was Dorothy Chads, followed in early 1940 by Mary Wilson, Sheila Dunlop and Jean d’E. Mylne. While Welchman was not involved directly in recruiting most of the female contingent in Hut 6, he did recruit two important women. The first was Joan Clarke, whom he had supervised in geometry for Part II of the Cambridge Tripos. She duly arrived at BP on 17 June 1940, but instead of working in Hut 6 was collected by Alan Turing and taken to work in Hut 8. She remained there for the rest of the war and in 1944 b
ecame its deputy head. As Welchman’s wife Katharine and son Nick were still living in Cambridge, he returned home as often as he could and on one such trip in early 1940, recruited June Canney and, in due course, drove her to BP. She would soon become his secretary and play a key role in the administration of Hut 6. As Welchman said jokingly to his agent many years later: ‘Sad that I was far too busy to take advantage of the society of so many attractive and intelligent young ladies.’4

  By 1941 the government had curtailed Welchman’s personal recruiting programme and introduced regulation. In reality, this simply meant getting access to scientists and mathematicians through C. P. Snow of Christ’s College, Cambridge. As Welchman had known him before the war, the flow of recruits to Hut 6 continued unabated. In any event, enough staff were already in place to begin populating the newly opened Hut 6 in late January 1940. While they had not yet broken any Enigma traffic, an organization was being put into place because Welchman was confident that it was only a matter of time before they were breaking large numbers of Enigma encrypted messages on a daily basis.

  Hut 6 formed the Production section and its subdivisions followed Welchman’s plan for a production-line approach.5 All intercepted traffic came into Hut 6’s Registration section headed by Welchman himself and as his deputy, Milner-Barry. By March, their team included Colman as statistician; a part time typist, Mrs P. H. Edwards; four team leaders including Howard Smith and Michael Banister; and seven female team members. The section’s job was to acquire a grasp of the whole German wireless traffic (W/T) organization, so that the available intercepting stations could be used to the best possible advantage. For this purpose they had to keep in close touch with the Intelligence Section in Hut 3, with the Air Section, with the Military Section, and with the intercepting stations. They watched for peculiarities in the traffic and for signs of any change in German procedures. Once Enigma results were produced they looked for ways that they could help other sections. They also investigated other lines of attack and, as far as possible, prepared themselves for emergencies. At the same time they had to keep abreast of all developments in Enigma theory and be ready to modify their methods of registration when necessary.