by Alastair Denniston- Code-breaking From Room 40 to Berkeley Street
To compile and be responsible for printing all codes and cyphers used by the British Government Departments with the sole exception of those mentioned in paragraph 5 below (this refers to Signal Books and purely Departmental Codes of the three fighting services. However, GC&CS was to advise on the general principles of their construction and the limitation of their ‘life’. GC& CS would decide on what is classified as Departmental Codes after consulting relevant Department).
To examine all the British Government Codes and cyphers now in force and the purpose for which they are used, mainly with a view to ascertain and, where necessary, increasing their degree of security; but also so as to ensure that messages shall be free from ambiguity and undue delay ensuing from mutilation in transit, and that they shall be coded in the most economical manner possible.
To maintain the closest liaison with all British Government Departments using codes and cyphers, and to advise them generally in matters relating thereto.
To instruct as large a proportion of Officers as possible who may be employed at any time in coding or cyphering.
To assist in the preparation of any hand-books or instructions relating to coding or cyphering, or of those concerning the handling of code and cypher messages in general.
It was suggested that the following departments appoint a Liaison Officer with GC&CS: War Office, Air Ministry, Foreign Office, India Office, Colonial Office, Ministry of Munitions, Ministry of Food, Ministry of Transport, General Post Office.
AGD’s new organisation was formally called the Government Code and Cypher School (GC&CS). The name itself was invented by Courtney Forbes, a member of the Communications Department of the Foreign Office. Publicly it was ‘to advise as to the security of codes and cyphers used by all Government departments and to assist in their provision’. However, its secret directive was ‘to study the methods of cypher communications used by foreign powers’. Pressure from DNI and others forced the inclusion in the new Official Secrets Act of a clause instructing all cable companies operating in the UK to hand over for scrutiny copies of all cable traffic passing over their systems within ten days of despatch or receipt. The discussions in 1919 made it clear that the Foreign Office and Lord Curzon recognised the potential of the diplomatic decrypts from GC&CS.15 Interestingly, the three services were expressly excluded from needing GC&CS’s advice.
GC&CS was up and running very quickly and its first decrypts were issued two days after its formation. The new organisation was housed as agreed in Watergate House in the Adelphi in London. Lieutenant-Commander Edward Travis16 was appointed to run the Construction Section and act as Deputy Head. Travis had experience of naval code book construction, so he took responsibility for cipher security while AGD supervised cipher-breaking. Travis also advised the Admiralty on communications security. However, GC&CS had no authority to advise on good security practice, so his role was limited. This may have led to his losing interest in security, hence the two Admiralty security staff assigned to GC&CS ended up working as cryptanalysts. In the end, the advice from GC&CS to the Admiralty about code and cipher security was very poor.
By December 1919, the GC&CS staff included five seniors (three from MI1(b), two from Room 40), seventeen juniors (ten from MI1(b) and six from Room 40, one from the Foreign Office), three female translators from MI1(b) and thirty female clerks for the Construction Section. Almost all of the traffic being dealt with was of a diplomatic or commercial nature, and it is estimated that between 1 November 1919 and 21 January 1920, 900 decrypts were distributed as follows: Argentina, Denmark, France, Italy, Japan, Norway, Persia, Romania, Sweden, United States, Uruguay: 54.3 per cent; Austria, Chile, Germany, Russia: 14.6 per cent; Greece, Spain: 26.8 per cent; Kingdom of the Hejaz, Poland, Syria: 4.3 per cent.17
In mid-1921, Curzon had succeeded Balfour as Foreign Secretary and described the work of GC&CS as ‘by far the most important branch of our confidential work. The decrypted telegrams of foreign Govts., are without doubt the most valuable source of our secret information respecting their policy and actions. They provide the most accurate and, withal, intrinsically the cheapest, means of obtaining secret political information that exists.’18 In February 1921, Walter Hulme Long, who was interested in intelligence matters, was replaced as First Lord at the Admiralty by Arthur Hamilton Lee. On 25 April 1921, Lord Curzon, who had previously argued for GC&CS to be in the Foreign Office, wrote to Lee:
I think I mentioned to you a little while ago that I proposed with your assent that the Code and Cypher School, which during the war was for very good reason placed under the Admiralty [Curzon seems to have forgotten about MI1(b)], should now be taken over by the Foreign Office, to which nine-tenths of its work appertains.
I was the Chairman of a Conference just two years ago … at which it was decided to continue the Code & Cypher School in existence [sic], and to house it, at any rate for the present, in the Admiralty. The reasons for this decision were that it would be undesirable to deprive the School of the shelter which the Admiralty buildings afforded, that the vote would be more likely to slip through the House of Commons if it came under the Admiralty disguise, and that the Foreign Office might feel more compunction if through the interviews of the Secretary of State with foreign Ambassadors and Ministers he were to profit by information which his own Department had secretly acquired [this rather obscure point does not appear in the minutes].
These reasons struck me at the time as very flimsy – nor did I entertain any of the qualms described in the last paragraph. I deferred however, to the representations of my colleagues … I now realise that [the arrangement] is both illogical and indefensible.
It is wrong in principle … the sphere of the activity of the School is now purely political, and the intelligence procured has, except in very rare cases, no relation to, and can be of no value to, the Admiralty.
In some cases, as you may know, our possession of the ciphers has been detected by foreign Powers, and in the consequent change of ciphers by them we have lost almost immeasurably.
I cannot doubt that there will be an increase in efficiency if the School is brought under the Foreign Office, since the greater part of its work ought to be done in the closest cooperation with us, and our experience of the matter is now very considerable.
Even the argument of the Admiralty ‘cover’ has ceased to apply; for whereas I was led to believe, two years ago, the Department was likely to be housed in the Admiralty building, it is now domiciled in separate quarters, as detached from one Office as from the other.
What has terrified me most has been the too generous and careless distribution of the material under the existing system. I have already been obliged to resume the powers conferred upon me by the Cabinet Committee of deciding to whom the intercepted telegrams should go, and the danger of a profuse or undiscriminating distribution, I hope, no longer exists.
In May, Lee, who had little interest in intelligence, agreed with Curzon’s views and Sinclair did not object. Another factor might well have been the proposed cuts in public expenditure which were aimed mainly at the armed services. These were introduced in 1922 and became known as the ‘Geddes Axe’.19
On 23 July 1921, the Foreign Office told the Treasury it was taking over GC&CS from the Admiralty along with its staff of eighty-seven and operating costs of £31,464 per year. The change was effected on 1 April 1922 for Treasury budgetary reasons. Sinclair returned to Intelligence as Head of SIS following the death in June of Mansfield Cumming, the Service’s first head.20 By September, he had arranged for GC&CS to come under his control. To appease the Service Ministries, who had complained vigorously in April 1923 that GC&CS had lost its interdepartmental character since it had come under the Foreign Office, the Foreign Office agreed to return five named individuals to the Admiralty in the event of war.21 The Permanent Under-Secretary at the Foreign Office, Sir Eyre Crowe, devised the compromise of AGD reporting to Sinclair as both Head of SIS and Director of GC&CS but in turn, Sinclair would report to t
he Foreign Office.22
Sinclair and his successor would remain both Head of SIS and Director of GC&CS for more than twenty years. While the armed services kept some intelligence-gathering expertise in the field,23 SIS in effect acquired monopoly control over British Sigint. This proved to be an effective strategy, and GC&CS provided Whitehall with a constant stream of intercepted and decrypted foreign governments’ telegrams. It read the communications of France, Italy, the United States and Japan, and that of many smaller countries. The historian John Ferris later noted that ‘the GC&CS was one of the world’s largest code-breaking agencies, perhaps the biggest; as effective as any other, better than most, possibly the best on earth between 1919 and 1935’.
AGD’s organisation had moved to Queens Gate in 1921 and when Sinclair took over in 1923, he brought SIS and GC&CS together. By 1925, they occupied the third and fourth floors of the Broadway Buildings. This move was opposed by Lord Curzon as it was in Kensington, two miles from Whitehall,24 but according to AGD, in Kensington ‘we were more comfortable rather remote from other departments’.25 At the end of 1923, GC&CS’s staff numbered ninety-one and Sinclair told the Foreign Office that he wanted to reorganise the Service to meet the demands of war.26 The burden of keeping GC&CS afloat fell on the shoulders of AGD and he regarded his organisation as ‘an adopted child of the Foreign Office with no family rights, and the poor relation of the SIS, whose peacetime activities left no cash to spare’. In reality, GC&CS’s funding was comparable to other parts of Sinclair’s Service. However, he rarely complained since his dogged fidelity as a public servant was equalled by his dislike of publicity. AGD’s problem was that because of the secrecy, few in Whitehall knew of the war-winning work of Room 40 and AGD’s organisation had few supporters. He was not in a strong position to fight for funds and staff in the lean interwar years. He and his colleagues worked on a shoestring and in a kind of Civil Service limbo. Most Whitehall insiders thought that Room 40 had been wound up at the end of WW1 and were unaware of AGD’s new organisation.
Sinclair met with AGD in January 1924 and confirmed that he wanted to integrate the work of GC&CS with that of SIS.27 GC&CS would be responsible for cryptography and SIS for the distribution of intelligence derived from them. SIS would also supply intelligence and criticism to GC&CS to assist cryptography. Section I of SIS was to ‘supply GC&CS with a list of general subjects on which to concentrate…Armed Forces Sections of SIS to collaborate’. GC&CS was to ‘have full access to SIS records’. By June 1924, because of the large volume of ‘intelligence product’ available, AGD was told to distribute it directly to GC&CS’s customer departments and send copies to Sinclair. However, SIS kept overall control of the distribution of ‘Sigint product’.
In 1924, the Cabinet appointed a committee, with General Romer as chairman to advise on the anti-aircraft defence of the UK. One of its recommendations was that the control of the ‘Wireless Interception Service’ should be taken over by AGD ‘at the request of the Fighting Services and with the consent of the Foreign Office’.28 To oversee formal coordination within the intelligence services, the ‘Cryptography and Interception Committee’ (later the ‘Co-ordination of W/T Interception Committee’) was set up.29 Sinclair chaired the committee, with membership drawn from the three Service Ministries and GC&CS. The Secretary was an SIS officer, Colonel Arthur Peel, who had previously been Assistant DNI to Sinclair during his tenure as DNI. Peel helped develop a relationship between GC&CS and the Metropolitan Police during the 1920s. In the late 1930s, he helped coordinate the development of wireless intercept service in the Dominions.30 The Committee’s remit went beyond interception and covered cryptanalytic training and war planning, although it never had a controlling role, only one of coordination. While the police interception work was initially intended for suspected illicit wireless transmitters in Britain, from 1927 they began to intercept diplomatic wireless traffic for GC&CS.31 A subcommittee was set up initially under Peel and then AGD from the mid-1930s. As it only met every two years, it was agreed in July 1928 to form a standing sub-committee which ‘should concentrate on formulating definitive recommendations, and should in future prepare agenda for the main committee’. This new ‘Y Sub-Committee’ as it became known, met fortnightly under AGD and included representatives from the three Services, Scotland Yard, the GPO and the Head of the W/T Board.
GC&CS had to handle its own telegram collection service with an SIS car collecting material from the General Post Office and commercial communications companies daily and delivering them to Broadway, where they were copied and returned within twenty-four hours. The Cable Intercept Section, under Henry Maine, controlled the collection effort. Similar collections took place in India, Tehran, Haifa and Jerusalem. Between 1920 and 1927, GC&CS was producing on average 3,500 reports annually. These were known as ‘flimsies’ or ‘BJs’ (the file covers used to circulate GC&CS reports in the Foreign Office were blue, hence ‘blue jackets’. Confusingly, in the early 1920s, army reports were referred to as ‘black jumbos’.)
The GC&CS reports were verbatim transcriptions of decrypted messages, translated unless the original was in English or French, in which case the customer would be able to read it for himself. GC&CS did not attempt to provide context or explanation apart from crossreferencing them with related reports. AGD told colleagues within GC&CS that their role at this point was simply decryption. This was openly opposed by some in GC&CS such as William Clarke of the Naval Section, a veteran of Room 40. He firmly believed that GC&CS should be producing intelligence reports, as its predecessor Room 40 had done. However, Sinclair and AGD knew that customer departments regarded intelligence assessments as their domain and would have resisted any attempt by GC&CS to overstep agreed boundaries.
The distribution of ‘BJs’ changed from a restricted circulation of Admiralty, Foreign Office and War Office to include the Prime Minister, Lord Privy Seal, Colonial Office, India Office, Air Ministry and the Home Office ‘Directorate of Intelligence’. GC&CS’s Naval Section was the first in GC&CS to be dedicated to military matters, and worked against specific foreign navies.
It was the only GC&CS military section funded by GC&CS and the only one to use non-cryptanalytic techniques such as traffic analysis. When GC&CS had moved to Foreign Office control, Clarke became one of GC&CS’s liaison officers to the Admiralty and eventually head of the new Naval Section in GC&CS. Sinclair, as a former DNI, took a personal interest in their work and Clarke frequently bypassed AGD. However, from 1925, Sinclair, AGD and the Admiralty put constraints on the overzealous Clarke.32
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With his heavy workload, AGD found it difficult to find time for friends and family. His wife Dorothy worked regularly at the Chelsea Day Nursery and at the Infant Welfare Centres in Chelsea and Shadwell and would continue to do so until 1939. The couple were very much in love and he talked freely to her about his work. When she became pregnant in 1924, they called the child ‘X’, assuming it was male. When their daughter Margaret was born instead on 21 May 1925, they called her ‘Y’. The much anticipated son Robin was born 19 months later on Christmas Day 1926. AGD was a good father, even though he was so busy, as Robin remembered:
Through all this my father was perhaps the most important part. When I fell downstairs during a party (at age four) I was brought down, screaming with pain and fear, to my father sitting alone in the drawing room, on plumped up cushions; and he read me Winnie the Pooh to our mutual delight until the panic was over. He went with me to fetch the car from the garage in King’s Street, and was interested to note that I noted that the steering did not work well, thanks to there being a puncture in one of the front tyres. He drove a snub-nosed Morris with great care, particularly down to Bartonon-Sea for the summer holidays, where we had a small bungalow and rented a bath hut. Modest family picnics, sea bathing, some agreeable adult company including several from the Office; the beginnings of golf and tennis.
Robin had a nanny called Sheila. She was young and the daughter of a serge
ant-major at Camberley. She was followed by a number of governesses, who he despised, until Dorothy decided to look after her own son, unusual in those days for those of their social standing. He attended nursery classes in Tedworth Square and then a day school called Mrs Spencers (an early form of elementary school, usually taught by women in their own homes) in South Kensington. ‘Y’ also went there and AGD would walk them to school every morning before catching the Underground from Gloucester Road to St James’ Park and his office at Broadway. AGD worked long hours, six days a week but took a few weeks off in the summer. As war came nearer, his holidays were frequently interrupted. He was a benign presence who obviously enjoyed family life. He often went to play golf or tennis but preferred if the family came with him. The family attended King George V’s funeral in January 1936, and Robin was the bearer of a bouquet for Mrs Stanley Baldwin when she visited Shadwell Infant Welfare Centre where Dorothy did volunteer work.
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In April 1927, information from a Chinese raid on the Soviet Embassy in Peking reached London. It revealed that Arcos, the official Soviet trading organisation in London, was a centre of Soviet espionage in Britain. On 12 May 1927, several hundred policemen raided the Arcos offices in ‘Soviet House’ at 49 Moorgate in London. Over several days, police and intelligence officials removed numerous documents. Considerable intelligence was obtained of interest to both Britain and the US. However, to justify the raid, the Government revealed to Parliament that the intelligence obtained demonstrated Russia’s hostile intentions with regard to diplomatic and trade relations. Remarkably, the Prime Minister revealed that Britain could read the most secret Soviet cipher traffic. This was to provide proof to the Government’s parliamentary opponents that the intelligence was accurate. However, it was done despite lobbying from AGD and Stewart Menzies,33 Assistant Director for Special Intelligence in SIS. As AGD later noted: ‘The only real operational intelligence came from our work on Soviet traffic. We were able to attack their systems step by step with success from the days of Litinov’s first visit to Copenhagen, of Kamenev as their first representative in London followed by Krassin.’34 The Soviet reaction to the Prime Minister’s statement was immediate: ‘Until the famous Arcos Raid in 1927 when HMG found it necessary to compromise our work beyond any question. From that time the Soviet Government introduced OTPs [one-time pads]35 for their diplomatic and commercial traffic to all capitals where they had diplomatic representatives.’ However, Soviet diplomatic traffic continued to be read by GC&CS for some time.
