The friendship established between the legendary cryptanalyst William Friedman and my father was to give a strong base of trust and understanding to what was to become an Anglo-American joint enterprise handling of all signals intelligence. It was already well established when Friedman and his colleagues Colonel McCormack and Brigadier Telford Taylor arrived in England on 25 April 1943. By September, and despite setbacks, the agreement on complete cooperation between the two countries ‘in all matters pertaining to Special Intelligence’ had borne fruit. His own friendship with Friedman was also to last until his death in 1961. Many years later, in 1961, Friedman wrote to my sister:
Dear ‘Y’
…. Your father was a great man, in whose debt all English-speaking people will remain for a very long time, if not for ever. That so very few of them should know exactly what he did towards achievement of victory in World War I and II is the sad part of the untold story of his life and of his great contribution to that victory. His devotion to the supremely important activities to which he gave so much of himself unstintingly, and with no thought to his own frail strength and physical welfare will never be forgotten by those of us who had the pleasure of knowing, admiring and loving him….
William F. Friedman
In 1941 he was still an ill man (his diary records ‘neuritis begins’ on 26 August). Yet only a week after his return he was flying westwards again, this time to Canada. The expenses of that journey included a bill for £283, which was not deducted from salary, but the doctor’s bill exceeded his net salary. On his second trip AGD flew to Toronto to brief the Canadians about British cryptographic achievements against the Japanese and warned that British material would not be made available unless the US cipher brain Herbert Yardley was removed. AGD’s diary notes with rare circumstantiality that ‘Montreal could train up to at least 100 W/T operators every three months’. That and the following week’s expenses amounted to £400, all recouped from a float of £500 issued to him in two separate amounts. His purchases included unusually lavish presents for his family. He flew back from Ottawa via Gander. The flight took 15 hours. He was the only passenger and was put in the bomb rack, where he wore an oxygen mask which he removed only to eat chocolate, which was all that sustained him. He got to Ayr at 11.30am on 13 September, travelling thence to Hendon and home to the isolated farmhouse near Bletchley that he had rented for the duration. On the previous and subsequent nights, RAF planes were shot down. His survival was regarded by his family as a miracle.
It is surprising that at the height of this crisis year at BP in 1941 my father should have made these trips. The circumstances of the visits are still unclear, given that the United States was not yet in the war and matters at Bletchley must have needed his full attention. The files are silent on the matter of authorization. Yet the outcome of these trips caused him the greatest satisfaction, amply justified by history. He returned with the outline of the plan for American involvement in Bletchley Park and Berkeley Street, and in due course a succession of American officers were seconded to work with GCHQ in the UK. This may have been a factor in determining the American decision to enter the war on the Allied side in December 1941, though Pearl Harbor made that decision inevitable.
By August all seemed to return to normal in Denniston’s professional life. America would not become our wartime ally for several more months. Without American involvement, despite Churchill’s brave words, Britain remained a hostage to Hitler’s master plan, or at least would find itself in desperate need of another Zimmermann telegram, another trigger to force American public opinion towards war. In 1941 few apart from Denniston knew about the management of the Zimmermann telegram, but no one of the calibre of Sir Reginald Hall was around to exploit it, though there were a few Anglo-American intelligence entrepreneurs like Sir William Stephenson who had influence but insufficient discretion.
Before August 1941 America was uninformed about Enigma. Denniston saw that the British could do for the Americans what the Poles had done for the British and French - make total unilateral disclosure; but to whom, and in return for what? It could only be the entrance of America into the war, by playing the Enigma card so skilfully that a result comparable to that of 1916 could be achieved. Denniston himself was unqualified for the work but he recognized its crucial importance. Menzies had neither the background nor the influence so it was to identify who should be the American recipient of the information that AGD flew to Washington in July 1941. In establishing friendly contacts with Friedman and the others he played the Enigma card - less spectacularly than Blinker Hall with the Zimmermann telegram because it took another six months and Pearl Harbor to achieve the objective – but as well as he could. And, as further evidence of the importance of the World War I precedent, Friedman and Denniston continued to correspond on the minutiae of the Zimmermann episode, till close to the latter’s death in 1961. In 1941 AGD had a similar opportunity to influence the course of a world war, recognize the opportunity, and play a modest part in turning defeat into victory.
On 19 September he saw Menzies. Later he met Vivian, de Grey, the DNI, and other friends, old and new. He continued to serve on the Y Committee. He had check-ups but had returned to reasonable health. We moved from the farmhouse to a small semi-detached house called Friedenheim just outside the gates of Bletchley Park, which now was renamed not GC&CS but GCHQ. Christmas dinner was celebrated en famille with ‘The Profs.’ - Boase, Last, and Adcock at Newton Longueville where the mother of a family friend, Rhoda Welsford, had rented the old rectory a mile from the gates of Bletchley Park. But pressures inside the gates were mounting. He remained as Director until 30 January 1942, when he was moved sideways to become DD(C) (Deputy Director in charge of commercial and diplomatic traffic) a fact that was duly noted without comment in his diary. The move to the gates of Bletchley Park was followed by a further move back to our house in Ashtead, Surrey (since he was to work in London), where he had lived before the war and whence a number of ultimately distinguished cryptographers had been recruited by him into GC&CS.
Ronald Lewin writes of AGD as a man of great charm and integrity, and a skilled and experienced cryptologist:
‘He could also no doubt have become a technical expert in breaking Enigma’s machine ciphers, but he carried the heavy administrative load involved in expanding his peacetime GC&CS into a wartime organization. His health was poor … he needed the support of a practical specialist, but the brightest star at his side, the scintillating Dilly Knox, was a man very specifically, of letters … Denniston’s personal contribution to the success of Ultra has not yet been properly appreciated.
What is certainly true is that Knox had mastered some of the theory behind Enigma even before the encounters with the French and the Poles, that the two of them so impressed the other parties when they met that, despite the official British Government passivity referred to by Bertrand, they were allotted crucial tasks in the undermining of Enigma’s secrets, and that Knox, even before the arrival of Welchman and Turing, had proceeded far into theoretical solutions. Thus, Knox was upset and irritated when these brilliant young mathematicians took over, Welchman developed the Bombe without which daily decrypts would have been impossible to achieve, and computers began to see the light of day. Welchman’s own account of this crucial and moving moment carries the sound of truth as well as innocence. So Knox perhaps deserves the credit for Enigma, and Denniston for Ultra.
Denniston’s relegation caused a tremendous rumpus, out of all proportion, one might think, to the actual event. The knighthood which was his due, in the view of a whole generation of veterans of the secret service, was not to be his. Charles Whiting believes that mutual dislike between Denniston and Menzies was the cause of the decision, with Menzies paying off old scores, demoting and finally retiring him on a pittance. F. W. Winterbotham more charitably reported: ‘It had been considered advisable to put all the departments at Bletchley under one director, Commander Travis, who was put in to replace Commander Denniston, t
he real founder of Ultra, now posted back to London on other cryptographic duties’.
Since the event signalled the beginning of his most successful years as a ‘total-service’ cryptanalyst, it is worth trying to find out what happened and why. AGD facilitated the arrival of the mathematicians and their solutions of machine decipherment, but he remained deeply worried about security. This was his obsession. All would be lost if Germany knew what we were reading. However difficult it would have been for the High Command to switch from Enigma they would certainly have done so, or at least made access many times more difficult, had they seriously suspected that they had been compromised. Elderly German ex-cryptographers still cannot believe the Bletchley achievement. That Denniston felt this so strongly was due to his length of service, which gave him a perspective and an understanding of the need for a total service, which was not available either to newcomers or to pure specialists, for whom problem-solving was the whole story. He was particularly worried about the arrival of Menzies. He had similar misgivings about Vivian’s arrival. My father had become paranoid about security, and hence a poor delegator and communicator. To Admiral Sinclair he could always talk, but his successor was very different. Menzies was a WWI hero and conducted most of his secret MI6 business at White’s Club in St. James’s and BP’s intellectual feats were simply beyond him. Also, as a manager of difficult and clever men he was almost useless.
The ill health which was the ostensible cause of my father’s removal was soon overcome, and once established at the Berkeley Street office ‘above Peggy Carter’s hat shop’ he never missed a day’s work until retirement. He accepted demotion and settled down to make the new job work. The embassy-listening post at Palmer Street was still active and provided plenty of material, as we shall see.
Confirmation of the quality and importance of the work of DD(C) and his team at Berkeley Street is not easy to come by. This is not only because of the official embargo, but also because of the office politics and personalities involved. The more successful the work the more some individuals wished to take it back to Bletchley Park and reincorporate it there. The only published story is a tantalizing one in Kim Philby’s My Silent War which is given some further context in Andrew Boyle’s The Climate of Treason. Given the scepticism (not always justified) with which Philby’s revelations have been received, it may be better to rely on the painstaking Boyle. It is clear from both accounts that the successful playing off of Berkeley Street and BP was a watershed in Philby’s career as a double agent.
In the autumn of 1943 Philby was in charge of the Italian, African, French, and Iberian counter-espionage sections, working from Ryder Street. His boss was Felix Cowgill and his current undercover job was to replace Cowgill by himself - a vital step in his own double career both in MI6 and in Russian intelligence. Several of their colleagues, American and British, knew what was going on. With Cowgill absent in America, Philby, promoted to be his deputy, raided his filing system and memorized a file of German Foreign Office material opened by the Americans and validated by Allen Dulles of OSS, despite rejection by the British. Dansey received copies and took the official British view of their authenticity: so Philby sent samples of the Dulles material to AGD, who quickly proved that the Americans were right and the British wrong. Philby sent more samples, which proved identical to some of Berkeley Street’s recent diplomatic intercepts with which they now hoped at last to crack the German diplomatic code, Floradora. Philby successfully exploited the animosities not only between Cowgill and the rest of the British establishment, but also between Bletchley and Berkeley Street, to further his career and international aims.
Berkeley Street was clearly no backwater, and this is confirmed by the fact that the Americans assigned a senior officer, Brigadier Telford Taylor, to work with the British on diplomatic traffic and later, Major Bancroft Littlefield. Harder evidence is adduced by Denniston’s official Number Two, Bill Filby, who writes that Denniston took with him the German, Japanese, Middle East, Portuguese, and Spanish groups, and
on seven floors we worked like beavers - for our hero, AGD. He was in every day, visited the sections almost daily, and encouraged all of us by the intimacy he had with the janitor to the heads of the sections. Obviously he was disappointed and extremely bitter, but whenever I went to stay with him and with Dorothy he was relaxed. The villain of the piece was really a man named Freeborn, leader of the machine group from Letchworth. He was power hungry and realized with AGD out of the way he could manipulate to his heart’s content. Even Travis would generally address Freeborn: ‘Mr Freeborn, we have a particularly difficult time in front of us. Do you think you could spare a few machines?’ Freeborn would look at a board and ruminate, and would finally state that if he cut A and B he could accommodate Travis. Having got his way he attacked AGD unmercifully, and because his Hollerith machines were now all powerful he virtually controlled all but Ultra. AGD was given the sop at Berkeley Street but to the horror of Freeborn it turned into a gigantic success for AGD. We used to work 18 hours a day, seven days a week as if to prove that AGD could control and direct. ‘C’ was always on good terms with AGD and one day in 1943 he was able to turn to AGD and congratulate him on a great success, with more to come. Freeborn called me in his office and he asked me to come back to Bletchley with my team. ‘Travis will OK it if you wish.’ I declined and he promised to stop further promotion.
Robert Cecil, one of Menzie’s senior staff, adds the following memoir:
Looking back, forty years on, I ask myself why I did not know him better. Part of the answer is to be found in the age gap. AD had made his reputation as a cryptanalyst in the first World War. But part of the answer must lie in the character of AD himself. He seemed a very self-contained Scot, perhaps a little dour. I think his long and sometimes discouraging experiences of GC&CS had etched in this characteristic more deeply. Between the wars, his work had suffered both the neglect of politicians, who had not provided enough resources, and the levity of politicians who, in a moment of loud-mouthed indignation, had given away to the Russians the hard-won insight into their cyphers.
When World War II came, money began to flow again and the huts rose up rapidly at Bletchley; but by then there were less scrupulous and more ambitious men on hand to skim off much of the credit. Denniston left Bletchley and came back to London to escape the back-biting and get on with the job; he disliked the in-fighting more than he feared the Luftwaffe.
These characteristics stood out in the period 1943-5, when I knew him. I was one of the personal assistants of ‘C’, Menzies. Heads of sections, each armed with a choice tit-bit of intelligence, used to carry it in to ‘C’ as if it was all their own work, in the hope of basking in the sunshine of vicarious success. Not so AD. He would make a careful selection of the most telling diplomatic intercepts (in the FO we used to call them ‘BJs’); but these were always sent to ‘C’ in a locked box by hand of messenger.
The diplomatic section has not achieved as much celebrity as the military section, which produced Enigma. We never read the top German diplomatic cypher, but we read all the Japanese and enough of the neutrals’ in the difficult days when most of them thought we should lose the war. When it was Hitler who was losing, the Germans were telling the Japanese everything that would keep them fighting in a lost cause. For example, they were telling the Japanese Embassy in Berlin all about the wonder-weapons V-one and V-two. They were telling us, too, though they did not know it.
Denniston always kept his ship on an even keel and his staff, who included a number of brilliant eccentrics, liked and respected him. One of them, whom I remember, had come down from Oxford with a First in Egyptology and had then become an astrologer; when his eccentricities began to affect his colleagues, Denniston just sent him on sick-leave and welcomed him back, when he was restored.
My father retained the special relationship of mutual trust and disclosure with the Americans. This is confirmed by letters from two American veteran cryptanalysts, Abraham Sinkov and F
rank Rowlett:
January 20, 1991
Dear Mr Denniston,
… I came to B.P. in early 1941 with a small team of Americans whose mission was to initiate collaboration in signal intelligence with the UK. We were greeted on our arrival by Cdr. Denniston who graciously welcomed us to our task and indicated how we would be accommodated and would function in our mission. … I remember that he was highly considered by the Bletchley personnel …
Abe Sinkov
30 April 1991
Dear Mr. Denniston
…. I remember well your father’s visit to Washington in August 1941. It was his visit which laid the foundations for the collaboration between the cryptologic activities of the US and the UK which produced intelligence vital to the successful prosecution of World War II. We spent considerable time together discussing the technical activities undertaken by both countries and worked out some of the details of our early collaborative efforts. Some months later I spent several days, at his installation in London where I was treated most graciously by your father and his staff. ….
Frank B. Rowlett
* Censored
* One-time pad - a system in which a private key generated randomly is used only once to encrypt a message that is then decrypted by the receiver using a matching one-time pad and key.
Thirty Secret Years Page 9