Dilly

by Batey, Mavis;

  Rejewski, however, with his colleagues, was able to work on known wheel wirings and had already produced a catalogue and a mechanical cyclometer to help break messages. At the time, Dilly did not know the wiring of the wheels, but proposed when he did to ascertain in the machine cycle where the same letters of the alphabet occurred at two places three positions apart; these he called ‘females’ and proposed to mark them on photographic film. He seems to have got some way with their production since in the memo he wrote after his visit to Warsaw, he says he ‘could not possibly have finished the tasks I gave myself but for AGD’s [Denniston’s] help even in technical matters’. This would be referring largely to having to get permission for funding for every piece of equipment required. When Dilly discussed his method with the Pyry codebreakers, although he felt his method would work, he conceded that the Polish idea of stacking Zygalski’s ‘perforated sheets’ was easier and cheaper. This would be his first task when war was declared and Bletchley Park, the war station for GC&CS, was established.

  SEVEN

  Bletchley Park as war station

  Bletchley Park was up and running when war was declared on 3 September 1939, thanks to the foresight of the Head of SIS, Admiral Sinclair, who was also the overall director of GC&CS. He was known as ‘C’ to both organisations (so called after the initial of the first head of SIS, Commander Mansfield Cumming). Sinclair was increasingly aware of the destructive power of aerial bombing on cities, so dramatically demonstrated in the Spanish Civil War. Believing that war was now inevitable, he wanted to find a safe place in the country for his various secret intelligence departments away from Broadway Buildings in Westminster. Early in 1938, he asked the Foreign Office to provide the funds, but was told that it was the War Office which was responsible for war. The generals told him that as a former head of naval intelligence he should go to the Admiralty, who reminded him he was now part of the Foreign Office; exasperated, he paid the £7,500 asking price for Bletchley Park himself. If he had waited until the war started, the stately home could have been requisitioned by the government. It was, however, an excellent choice as Bletchley was ideally situated. By road it was on the A5, the old Watling Street, and more importantly it had good communications links with London and was a junction on the main-line train service between London, the north of England and Scotland; it was also midway between Oxford and Cambridge, from where Alastair Denniston’s ‘professor types’ would be recruited, and the tree-studded lawns of a stately home would stand in for the groves of Academe.

  Sir Herbert Leon, the builder of the flamboyant Victorian mansion, had himself chosen the site since, as a financier, company director and active Liberal MP, he needed easy access to London. He had a pathway made through his grand gardens with a special exit to the station. This proved very useful for us in wartime, as well as a pleasant walk, and had a sentry on guard during daylight hours. Leon had been determined to be upsides with his nearby fellow Jewish Liberal financier Lord Rothschild, in his splendid house and garden at Waddesdon. Bletchley Park was built in the eclectic ‘Old English Revival’ style with oriental additions, ending up a dizzy mixture of Gothic windows and a copper dome with very lavish Jacobean interiors. The Americans who arrived to work there in 1943 could hardly believe their eyes. It then suggested to one observer ‘a 1920s movie palace’, which, ‘in coming to house the imaginative and mysterious activities of codebreaking, seemed at last to have acquired tenants to match its architecture’. They did, however, appreciate the ambience of the landscaped lake, although much of Leon’s grand garden had been built on, with a naval hut in the rose garden and another hut in the maze. The stately home certainly contributed to the paradoxically relaxed atmosphere of Bletchley Park as a war station.

  Sinclair was very aware of the need to upgrade security for SIS communications systems for both intelligence-gathering and dissemination of secret information. He recruited Richard Gambier-Parry from Philco Radio and put him in charge of a new division of SIS, known as Section VIII, to handle all its communications. Some of its representatives arrived on the site as soon as Sinclair purchased Bletchley Park for his overall organisation in March 1938. They were also present at the rehearsal in August 1938 to test Bletchley Park for all the SIS departments; called ‘Captain Ridley’s shooting party’ to put the locals off the scent, it was organised by an SIS administrative officer, a real Captain W. H. W. Ridley. By all accounts it was a very pleasant occasion, Sinclair having brought his favourite chef from the Savoy Grill with him.

  GC&CS was certainly not to be the only occupant of what was first called ‘Station X’, named after its wireless station. They returned to London in October 1938, after the Munich agreement, leaving Gambier-Parry’s team in occupation. Staff from his Section VIII occupied the upper floor of the mansion and its engineers built a wireless telegraphy station in its tower. The Victorian grounds were full of mature conifers and the aerial was slung to the top of a Sequoiadendron giganteum on the front lawn. This was all part of the war station and intended to duplicate the existing SIS wireless ‘Station X’ at Barnes in west London. The plan was that the Barnes station would, like all SIS sections, be fully transferred to Bletchley Park in event of war. Some people, especially the Americans when they arrived in 1943, liked the cloak-and-dagger sound of ‘Station X’ and continued to refer to it as such during and after the war. However, almost everyone working there or connected with the place throughout the war referred to it as ‘the Park’ or more simply ‘BP’.

  In November 1939, the notorious ‘Venlo incident’, in which two SIS officers based in Holland, Major Richard Stevens and Sigismund Payne Best, were kidnapped by the Germans at Venlo on the Dutch border and taken into Germany, where they gave away a large amount of detail about British intelligence, led the new head of SIS, Colonel Stewart Menzies, to decide that having GC&CS on the same site as the SIS wireless communications centre was not a good idea. The SIS radio station and Section VIII of SIS, which in any case needed to expand, were soon transferred to nearby Whaddon Hall, along with the aerials and all the wireless gear needed for covert signals, leaving GC&CS as sole occupant of Bletchley Park. The capture of the two SIS officers at Venlo, one of them carrying a list of his agents, had sent shock waves through the Foreign Office and SIS. We are fully informed of quite how much Payne Best and Stevens had given away after the war by a remarkable Gestapo handbook by SS General Walter Schellenberg, who had been in on the Venlo incident. Its purpose was to give Hitler’s staff planning the 1940 invasion a detailed analysis of the political and economic structure of the country. The chapter on British intelligence, operating from Broadway Buildings, provided largely by Stevens and Payne Best, was astonishingly accurate. The Germans positioned an agent, posing as a match seller, outside St James’s Park Underground station opposite Broadway Buildings, to take photographs of the people going in and out. I worked there myself at the beginning of 1940 and would be intrigued to know whether I was in a Nazi file. A floor-by-floor breakdown of the departments was given, naming their heads. A special wanted list of those to be arrested even gave their home addresses and in some cases car registration numbers.

  Sinclair was originally in charge, the handbook said, but on 4 November had been replaced by ‘a Scotsman’ called Colonel Stuart (sic) Menzies, who was ‘pronounced Mengis’. It referred to the administrative, military, naval and air sections. The head of the air section was said to be Wing Commander Winter-Bottom; the rank was right but his name was in fact Frederick Winterbotham. It also referred to the communications section, which Stevens claimed to know nothing about but which was allegedly headed by a ‘Gambier Perry [sic], calls himself a Colonel but this seems to be untrue’ and was ‘reputed to have moved to Bletchley. Duties: wireless/radio communications, telephone, pigeon-post, etc.’ A cipher section was mentioned somewhere else but its duties were said to be the preparation of our own codes and gave no Bletchley connection.

  Mercifully the SIS policy of ‘need to know’ proved its
worth. Even under torture Stevens could not have divulged the secrets of codebreaking, as he simply did not know it was being successfully undertaken. The information about Bletchley seems to have come from local fifth-column observation as there was a plaque on the gate saying ‘Government Communications’. The term ‘communications’ is intentionally ambiguous, especially in translation, and gives no hint of codebreaking and there really were carrier pigeons in the stable-yard – SIS still used them at this stage – which provided a perfect alibi for what we were doing. It does not appear that Schellenberg’s informative handbook was passed on to anyone else when the invasion was called off, otherwise the Luftwaffe would surely have dropped a bigger bomb on Bletchley Park than the half-hearted string of bomblets that was accidentally dropped on one occasion and did little damage.

  The importance of GC&CS’s activities had now risen considerably in the field of intelligence gathering. Signals intelligence, ‘special intelligence’ as it was then called, would for some considerable time have to take the place of agents. It was now imperative that Dilly and his team, installed in the Cottage, should be able to read current enemy traffic. A photograph of Captain Ridley’s 1938 shooting party, taken by Barbara Abernethy, Alastair Denniston’s secretary, shows Dilly in serious discussion with Oliver Strachey out of range of the main party. While the other chief players had been deciding on appropriate accommodation downstairs in the main part of the mansion, he had earmarked for himself a former groom’s cottage in the stable-yard (where the pigeon loft was situated), well away from any kind of administrative contact. Commander Denniston had chosen Lady Leon’s morning room to the left of the mansion entrance as you looked at it from the circular driveway, so that he could keep an eye on everybody, just as ‘the little man’ had done in the Alice in ID25 pantomime. ‘Nobby’ Clarke, the head of the naval section, settled for the library, John Tiltman’s military section was assigned to the dining room and Josh Cooper, head of the air section, had his eye on the drawing room to the right of the entrance; he was still recovering from his journey from London. ‘MI6 provided some cars for transport but many people used their own cars and gave lifts to others,’ he recalled. ‘It fell to my lot to be driven down by Knox, who had a remarkable theory that the best way to avoid accidents was to take every crossroad at maximum speed.’

  After the war station was put into action in August 1939, Dilly immediately settled into his stable-yard cottage and made plans to receive his staff for his new Enigma research section when war broke out. He had always worked as a loner even when he had assistants and it would be a new experience to run a section, albeit initially a small one, with Tony Kendrick and Peter Twinn already part of the team. One career civil servant clerk, Joyce Fox-Mail, was allocated to him and Denniston sent along two new recruits, Elizabeth Granger and Claire Harding, the daughters of two members of his Ashtead Golf Club whom he knew well, to settle him in; they were reliably discreet and indispensable in getting things organised. The ‘professor type’ codebreakers, who had all been placed on the ‘emergency list’, then arrived on 3 September 1939 and Dilly was waiting to greet them. They included Alan Turing from King’s College, Cambridge, Gordon Welchman from Sidney Sussex College, Cambridge, and John Jeffreys from Downing College, also Cambridge. They would all make significant contributions to the exploitations of the initial breaking of the Enigma machine.

  Dilly’s first task was to fulfil his promise of contacting and co-operating with the Poles. As the German armoured columns advanced on Warsaw, Rejewski, Zygalski and Różycki destroyed all their documents and equipment and managed to cross the Romanian frontier. In October, with the help of the French embassy, they reached Gustave Bertrand’s wartime Cipher Bureau, codenamed PC Bruno, which he had set up in the Château de Vignolles at Gretz-Armainvillers, near Paris. GC&CS made immediate contact with them and, urged on by Dilly, asked if Marian Rejewski and his colleagues could be allowed to join the codebreakers at Bletchley Park. However, it was made clear that ‘the French government were paying for the Polish army and therefore the Poles must work in France’. Relations with Bertrand, however, were extremely good. Dilly was always at pains to see that he was kept informed of progress and approved of arrangements. In fact a permanent liaison officer, Captain Kenneth Macfarlan, called ‘Pinky’ because of his rosy complexion, operated at PC Bruno and through him Bertrand had a direct teleprinter service with Denniston at Bletchley Park.

  Bertrand’s chief cryptographer, Henri Braquenié, whom Dilly had first met at the Paris conference in January 1939, came over to work in the Cottage in September soon after war was declared. Dilly, having seized him by the arm and rejoiced ‘Nous marchons ensemble’ at the Warsaw conference, was as good as his word. While he was at Bletchley Park, Braquenié stayed with Dilly at Courns Wood. On 29 September, Dilly wrote to Denniston: ‘It has been a great pleasure to me, though somewhat testing of my French, to bear-lead Captain B from 8 a.m. to 10 p.m.’ In a memo on ‘Anglo-French Enigma Liaison’, sub-titled ‘Finance’, Dilly pointed out:

  I have taken the line, though he offered to pay generously, that entertainment is une affaire de bureau; that is from my angle, that I should get a billeting allowance from you and that you or he should deal with the French. Drinks and transport other than that to or from the office (for which I get an allowance) I treat as my private liability.

  Dilly was no wine connoisseur and one can only wonder how the entente cordiale survived, as Oliver Knox said that at Courns Wood even the odd admiral would be entertained with just a half-bottle of plonk.

  The first task was to provide the quantities of Zygalski sheets for Bertrand’s PC Bruno centre that Dilly’s Polish friends needed. They had not had the resources to produce the number they needed after the Germans had added two extra wheels in autumn 1938. Jeffreys was put in charge of organising the ‘sex statistics’, as Dilly called the perforated sheets, tracking down ‘female’ positions in the machine cycle. A ‘female’ was a letter in the second group of a doubly enciphered Enigma message key which repeated a letter in the corresponding position in the first group, such as AFO, CFK.

  A special machine was made for producing the Netz, as they were usually called, which was under Dilly’s constant supervision. Denniston was invited over to the Cottage to punch the two-millionth hole and Harding and Grainger assisted Dilly in organising a ‘punch’ party; they said that he took endless pains to acquire the right ingredients for a wartime punch bowl. It was probably Braquenié who took the first batch of Zygalski sheets back to Bertrand’s PC Bruno centre, where he worked side by side with the Poles until the fall of France. They were working day and night in the Cottage but Dilly was not satisfied that things were going fast enough at the administrative level. As usual, he had the highest praise for his underpaid ‘girls’, who, he said, worked long hours punching and never mentioned overtime. It was no small achievement by the Cottage team since sixty sets of twenty-six sheets had to be made, with many of the sheets containing 1,000 precisely cut holes. PC Bruno was also sent copies of the ‘Jeffreys sheets’, which were punched-sheet catalogues showing the effect of any two wheels and the Umkehrwalze, the Enigma machine’s reflector. Pam Brewster, who had worked on perforating the sheets from the beginning and went on with the other girls to be a member of the teams who used the sheets in a process they called ‘Netz shoving’, recalls the excitement when the light bulb revealed an alignment of holes and the testing for female positions could begin.

  Although he had been anxious to supervise all that was going on, Dilly was not really any good at organisation. Welchman was just the man who was needed to come to grips with the as yet unsorted traffic networks through their call-signs and discriminants. As Welchman himself said, when he came to write The Hut Six Story, published in 1982: ‘Dilly was neither an organisation man nor a technical man. He was essentially an idea-struck man.’ Welchman and the old hand Tony Kendrick were dispatched to Elmer’s School, which had just been acquired on the edge of Bletchle
y Park. As there were large empty tables there it was an ideal place for this essential task of sorting messages, given that every surface in the tiny cottage was taken up with the punching of the perforated sheets. Braquenié had provided sheaves of old French intercepted Enigma traffic and Dilly, through Tiltman, arranged for Welchman and Kendrick to visit the army intercept station at Fort Bridgewoods, Chatham, in Kent, to see how all the messages were received before they were sent to Bletchley Park.

  Welchman’s work was truly productive. In retrospect, he saw that it set the scene for Hut 6 when the Cottage research would turn into production. He recalled how Kendrick, having been with Dilly in the early stages, explained to him how far their Enigma research had got and had suggested how their present assignment should be approached:

  Kendrick started to work on the large collection of material from Chatham, and set me a good example by beginning to analyse its characteristics in a methodical manner. His approach was reminiscent of the period some five or ten years earlier when I had been doing work on algebraic geometry and had often been faced with the problem of thinking of something to think about.

  Kendrick was dealing with the problem in the same way, he said, and ‘I followed suit’.