‘In 1939, I was interviewed in St. John’s College, Cambridge, briefly and informally, by two men I came to know very well: A. G. Denniston, the head of Bletchley, and John Tiltman, the chief cryptanalyst.’ (Codebreakers p.77)
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VII
Churchill himself was no stranger to the type of work done at Bletchley Park. 25 years earlier, as First Lord of the Admiralty, he had drawn up the protocol under which naval intercepts of German navy signals were decrypted, translated and assessed in Room 40 at the Admiralty. The orders he then issued to cryptographers, among them my father, were unworkable but the thinking behind them was sound. Britain had a secret weapon of vital importance to the war effort if properly and discreetly used. Room 40’s great triumph in World War One was the breaking of the Zimmerman telegram, in which the German Foreign Office urged Mexico into the war against the United States. Decrypted by two of my father’s colleagues, the Rev. William Montgomery and Nigel de Grey, it was successfully ‘spun’ by Admiral Hall, his boss, and eventually became instrumental in bringing America into the European conflict. In 1924 Churchill told Austen Chamberlain, ‘All the years I have been in office since the autumn of 1914 I have read every one of these flimsies (papers on which relevant messages were distributed in Whitehall) and attach more importance to them … than to any other source of knowledge at the disposal of the state’.
The ‘flimsies’ had by this time been called ‘bjs’ (blue jackets). My father, who in 1919 was appointed head of the Government Code and Cipher School, took forward the work of Room 40 into and beyond the interwar years; thus he and his colleagues all knew in 1940 that GC&CS had in the new prime minister a keenly attuned ear and eye to their product – information on the German Wehrmacht provided, on a daily basis, in absolute secrecy.
Throughout the interwar years Churchill, mostly out of office, still saw bjs, probably through his friend Major Desmond Morton, and read the monthly volumes circulated to a few in Whitehall.
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VIII
After February 1942 AGD and about 70 staff from the diplomatic section at BP (housed separately from the main buildings at Elmers End) removed from Bletchley, so they had just over a year to re-establish themselves in Berkeley Street, above a couturier’s shop. The staff grew rapidly in numbers to 200 including the commercial section (the suppliers of information to the Ministry of Economic Warfare on German imports of manganese, bauxite and other raw material for making war) in nearby Aldford House in Park Lane. It was a simple job to re-establish the way they worked at 55 Broadway before the war. They were well dug in by May 1943 when Colonel McCormack made his recently declassified report on British diplo successes against enemy, neutral and friendly nations.
In that time the war itself had at long last turned in the Allies’ favour. The low point, for Churchill, had been the fall of Singapore in March 1942, while the war at sea was still dominated by Doenitz’s U-Boats whose cryptographers had early on mastered the British naval ciphers, though BP’s success against German naval enciphering, still spasmodic in 1943, was eventually to give our admirals the upper hand, so that convoys could cross the Atlantic to and fro without catastrophic losses in naval tonnage, which Churchill admitted in his subsequent war history ‘gutted my bowels’. Victories in North Africa and some successful negotiations with Palestine and Transjordan still occupied him as well as ‘getting Turkey in’. Wavell’s low level international diplomacy irritated the great man until he found in General Auchinleck a less risk-averse commander-in-chief for the whole area. At this point Churchill turned his attention to the neutrals in general and Turkey in particular. Earlier Churchill had written to General Inonu, the Turkish premier, giving him good strategic advice on how to keep his country out of trouble by letting the Anglo-Saxons use his aerodromes to take off against the Luftwaffe and thereby try to wrest air supremacy from the Germans in the Eastern Mediterranean. The notion of air supremacy was news to the Turkish generals who had few combat aircraft of their own, no knowledge of the new wonders of radar, still less of international cipher-breaking now practised by both sides, so Inonu remained unconvinced, and stayed that way throughout the war, equally unimpressed by similar German diplomacy, conducted by their highly placed ambassador, Fritz von Papen, in Ankara.
So AGD’s diplomatic and economic work moved to the forefront of Churchill’s armament of information which by mid-1943 was thought of as equal in importance to BP’s service work; Colonel McCormack’s report makes this clear. But before the full account of this magisterial report, a confirmation of the high standing of Berkeley Street is to be found in a rarely cited message: Philby’s dry account of how he involved AGD in the study and use of thousands of mostly Ankara-Berlin diplomatic decrypts Philby had obtained by sleight of hand from Allen Dulles in Switzerland: solving these finally enabled AGD and his colleagues to break the German diplomatic cipher. For Philby explains to his readers – primarily the KGB in Moscow, followed by the many Russian readers who liked spy memoirs as much as British readers did, and eventually to readers in half a dozen foreign languages, including Serbo-Croat – that he went to AGD rather than BP since it was common knowledge for the cognoscenti that Menzies had hived off diplo from service traffic the previous year. Philby’s memoir was published in 1976, some years before the existence of Bletchley Park and its war work and workers were officially acknowledged.
According to P.W. Filby (no relation), Berkeley Street worked 18 hours a day 7 days a week, and achieved many successes. Colonel Alfred McCormack, the influential deputy head of the US army’s special branch, which supervised signal intelligence in the US War Department, was extremely impressed by Berkeley St. during a lengthy visit to GC&CS in 1943. He informed the department that ‘it would be absolutely astonished ‘by the resources of intelligence … here in Denniston’s show, waiting for someone to tap them’ (cable 4952 of 2 June 1943, ‘Colonel McCormack’s trip to London) - Denniston continuing his policy of co-operating fully with the US, had turned his people over to us for questioning and give us a free run of his place, more than anyone else in GC&CS (conversations with Denniston) Colonel McCormack’s trip to London’.
McCormack wrote lengthy reports on Berkeley Street which the National Archives in Washington DC released only recently.
McCormack was not the only officer to be impressed by Berkeley Street and its 62-year-old head. Brigadier Telford Taylor, who later went on to understudy the chief American prosecutor at the Nuremberg trials, became a close family friend and used to come to our house at weekends, where he played tennis, swam and drank whisky which he thoughtfully brought with him as it was unobtainable round our way. My mother and sister both fell in love with him – this handsome hero, like Cary Grant, my mother said later, but taller. Telford, my father and I went on a bicycle tour of the Cotswolds that year and I have a photo somewhere of the brigadier in full uniform mounting my mother’s low crossbar bike (skirts were worn by lady bicyclists) about to pedal up the long hills on deserted roads.
* MAGIC was the code assigned to Japanese diplomatic traffic intercepted by US intelligence as a result of the breaking of Purple, the Japanese diplomatic code, in 1940.
** Herbert Yardley, a maverick American cipher-brain, was considered a security risk.
CHAPTER TWO
Room 40: 1914-15
Written by A. G. Denniston in 1919, and now held at Churchill College, Cambridge as DENN1/2
This is the personal memoir of the build up and staffing of Room 40, the government’s signals intelligence centre in Whitehall. Work started in 1914 and as the scope of the work increased new talent – people with fresh blood – were needed. Yet there were never more than 40 people working full time shifts on the deciphering work. It will be necessary to mention many names but without giving the biography of the owner. In the earlier stages of development, new men were sought who had but two qualifications; a good knowledge of German and a reputation for discretion.
Cryptographers did not exist
, so far as one knew. A mathematical mind was alleged to be the best foundation, but it must be noted that except for Sir Alfred Ewing, Henderson, Russell Clarke and Hopkinson, no one had such a reputation, and in fact the majority of those chosen had actually had a classical training. As time went on, when assistance of a less skilled nature was urgently required to work for these self-trained cryptographers who knew German, ladies with a university education and wounded officers unfit for active service were brought in, and finally expert typists were admitted when the need for their help was almost too apparent. It should be noted in the light of later experience that the last should have been the first, or at any rate let it be said that every expert cryptographer must possess at least one typist skilled in sorting, filing and analyzing.
On the outbreak of War in late 1914, the Admiralty W/T station appointed for police duty received various signals, of which the only thing that could be said was that they were not British. These were at once supplemented by signals intercepted by various stations belonging to the Marconi Co. and to the Post Office. The Admiral in charge had no staff prepared to deal with this unknown and unexpected occurrence. He therefore suggested to Sir Alfred Ewing, the Director of Naval Education, that Education would probably be considered of little importance for the next few months and that, further, this mass of intercepted telegrams was possibly in code, a subject in which the D of E was known to have interested himself. He also provided Sir Alfred with the photograph copy of a German Code obtained by the Secret Service. (This ultimately proved to be no good).
Teachers at the naval colleges of Osborne and Dartmouth being on leave, the D of E was able to obtain the services of several of the modern language men from these colleges and thus it happened that several men who ultimately became permanent members joined up temporarily in August 1914 (including myself, Anstie, Hooper and Bond who all first met German signals at this period).
It is necessary to digress here to introduce the activities of the War Office. The same phenomena of intercepts had been observed in the Military Intelligence Directorate and in the first week of the war Colonel Macdonagh called in Sir Alfred Ewing to inform him that the W.O. had instructed Brigadier General Anderson to investigate these intercepts and to propose some form of amalgamation. Sir Alfred agreed to send a representative to work with General Anderson and what might be called the prenatal life of the cryptographic section began.
In those days the very amateur and inexperienced staff were greatly elated if they could obtain some sense from the P/L intercepts. It was the time now of the German advance into France, and their movements could be directly observed from the study of the en clair. Code and cypher were however not neglected. Sir Alfred’s party had fastened on to an obvious 10 letter code sent out by what were now known to be high power German stations to receiving stations in Africa and elsewhere. The staff included no one who knew anything of W/T procedure but, with the help of Mr Bradfield, a manager of the Marconi Co., various call signs were identified as German possessions. Code books of German commercial firms were collected and the investigations proceeded without, however, any discovery beyond the fact that Germany was communicating with her colonial governors and others.
The staff under General Anderson learned how to analyze. This they did with the utmost enthusiasm and entire lack of discretion. It was afterwards clear that military cypher messages were confused with naval codes and call signs figured as standard groups. But this staff did learn how to file and analyze. In the course of a few weeks codes and cyphers could be separated, and when about the middle of September the French gave G.H.Q. the method and the key of the military cyphers, no time was lost in settling down to decipher. Watch keeping was organised in the W.O. with the assistance of some of Sir Alfred’s staff and the improvement in W/T interception began to make itself felt.
Early in September, Russell Clarke called on the D of E and told him that he and his friend, Hippisley, had been obtaining German intercepts on their receiving sets in London and Wales. Both these men had been enthusiastic W/T amateurs since the earliest Q days. It is not clear why the police or the Post Office had not sealed up their apparatus, but it can well be imagined that some rash official had tried his best on Russell Clarke and had been forced to retire the worse for wear. These two men had no difficulty in persuading the D of E that, given reasonable conditions, they could produce all that was needed by the Admiralty to study the intercepted signals of the German grand fleet.
Sir Alfred obtained permission for them to install their apparatus at Hunstanton Coast Guard Station. Geographically the position was most satisfactory for the tapping of the Flanders air and, as events soon proved, it was the ideal place for the work they were soon to initiate and develop to such perfection. But Hunstanton was chosen because there was a Coast Guard Station equipped with W/T and it was suitable for interception in Flanders and North France. Russell Clarke and Hippisley brought along another W/T amateur, Lambert, and with the assistance of C.G. P.O., a continuous watch on the German field stations was kept, thus giving a very necessary duplication to Stockton (the Admiralty police station) and the Marconi stations. Work on these cyphers continued in the Admiralty and W.O. by day, while the night watch worked in the W.O.
One is bound to admit that the signs of jealousy were not absent even in this small section of men drawn from many branches of civil life. It must be remembered that, at this time, civilians deciphered and translated the messages which all concerned the Western Front and were of immediate value to the Intelligence Section of G.H.Q. whither they were transmitted by wire and by daily bag. But it must also be remembered that by day they were also deciphered and translated in the Admiralty, and if of no immediate value, they were occasionally of extreme interest and could hardly be concealed from those in supreme control. It is said that a climax was reached when the all highest on one side of Whitehall was told a translation of great interest (actually, proposals for treatment of Indian prisoners) by his opposite number before his own section had managed to get the information through to him.
It might be stated here that the colleges had now reopened and had claimed the services of certain of their staff who had worked with the D of E during August and September. Sir Alfred’s staff therefore now consisted of Naval Instructors Parish and Curtis, and Professor Renderson when their other duties permitted them and, as watchkeepers doing night duty in the W.O., Denniston (who had obtained leave from Osborne), Hershall and Norton. The first three knew something of mathematics and little of German; all six were singularly ignorant of cryptography, but they were becoming expert analyzers, filers and translators of German military telegraphese.
Most likely they were never in the office altogether for it was the Director of Education’s room and was crowded for three. Likewise, Sir Alfred had a certain amount of naval education to look after and people to see in his office, and occasionally it was necessary for the cryptographers(!) suddenly to pack up their papers as innocently as possible and scuttle into the small box-like room occupied by Mountstephen, Sir Alfred’s secretary. Sometime about the middle of October, Sir Alfred’s desk was cleared mysteriously and frequently on the arrival of the Russian attaché. There were some days of tense peace when little was seen of the D of E and the cryptographers were almost rudely discouraged from their visits to Mountstephen’s room, now occupied by an unknown naval officer, who came early and stayed late. Sir Alfred encouraged the sorters to seek out the hitherto neglected messages, all of which disappeared. Then, one fine day, the D of E remarked that it was blowing hard in the German Bight and in reply to direct questions explained what was afoot.
The Russian Naval attaché had brought a copy of the German Naval Signal Book which had been salved from the light cruiser Magdeburg. The quiet ever-working Naval Officer was Fleet Paymaster Rotter, the Head of the German Section of the Intelligence Division, whom the D.I.D. had lent to assist in tackling the new problem. The Russians alleged that the salved book was the one now in force in th
e German Navy, and that any naval intercepts we possessed must be decipherable by that book.
So far it had been discovered that the weather reports alone came directly out of the book and that all other signals were submitted to some process of reciphering which Rotter was now investigating. In a few days he solved the key which proved to be simple substitution, and within a few days of the solution the key changed! He set to work again and in a short time produced the current key which was to last for three months.
The material he had to work on was the numbered series of messages sent out by Nordderch (K.A.V.) to all ships (A.S.). The Germans, whose folly was greater than our stupidity, reciphered the numbers of the messages thus offering the simplest and surest entree into their reciphering tables. Before very long, Rotter was able to instruct the office in the use of the Signal Book and the key, and the current messages could be read.
Then Russell Clarke happened to come up from Hunstanton and look into the office. He saw these new signals and exclaimed that he could intercept hundreds of such messages daily on short waves which, if read, would give the daily doings of the German Fleet. K.A.V. to all ships were merely the intelligence reports circulated by the German naval staff concerning the movements of enemy shipping. The movements of the German Fleet would be of supreme interest.
There was, however, only one aerial at Hunstanton which was doing good work on military interception, and the D of E was a little loathe to lose good stuff for a pig in a poke. However, he agreed to a week-end trial which was of course conclusive. From what we could read of the stuff intercepted at Hunstanton alone, it was clear that we should from now onwards be able to follow every movement of the enemy fleet, provided always they used the same key, call signs and book.
Thirty Secret Years Page 3