GCHQ. Richard Aldrich

and had similarly told President Truman that mid-1953 was the most likely date. Shocked by the surprise atomic test, Britain and America now redoubled their intelligence effort in the field of Soviet strategic weapons.³ Throughout the Cold War, the key target for GCHQ would remain Soviet nuclear weaponry. This included not only the atomic bomb programme, but work on ballistic missiles, bombers and other means of delivery. The Chiefs of Staff were worried by Britain’s relative vulnerability to nuclear attack, and wanted intelligence forecasts on this crucial issue. In their list of ‘sigint targets’ for 1948, the JIC exhorted Britain’s code-breakers to focus their efforts on this area, together with parallel strategic threats such as chemical and biological weapons.⁴ Other Soviet activities, including KGB espionage and diplomatic initiatives, only constituted GCHQ’s second and third priorities.

      But ever since the massive revision of Soviet cypher procedure on ‘Black Friday’ in 1948, GCHQ had been having a hard time with its main target. The one-time pads employed for the highest-grade Soviet messages were now being correctly used, and so could not be broken, and machine cypher procedure on systems like Taper, effectively a Soviet military version of Enigma, had also been tightened up. Moreover, Moscow and its satellites enjoyed common borders and so often used landlines instead of wireless transmissions, which could not be easily intercepted. All this eventually prompted the British to follow the Soviets down the path of more extensive physical bugging of diplomatic premises in the mid-1950s.⁵

      GCHQ was nevertheless providing Whitehall with large quantities of useful material on lower-priority issues. It continued its long tradition of attacking the communications of smaller states like France, Turkey and Egypt. The JIC had also asked it to look at subjects such as Arab nationalism and the relations of Arab states with Britain and the USA, and the attitude of France, Italy and the Arab states to the future of North Africa, especially Libya. Because of the ongoing insurgency in Palestine, GCHQ was also urged to focus on the Zionist movement, including its various intelligence services. All of these proved more accessible than Soviet traffic.⁶ The diplomatic traffic of smaller states also provided an excellent window on the Soviets. Conversations between Soviet diplomats and the officials of these countries were often captured in telegrams sent from Moscow that could be read with ease. In 1946 Alan Stripp, a British code-breaker who had spent the war working on Japanese codes, found himself redeployed to the Iranian border. Throughout the Azerbaijan crisis of that year, when the Soviet Union appeared to be behind a potential breakaway state in northern Iran, he worked on Iranian and Afghan communications.⁷ This sigint revealed the scale of Soviet activities and ambitions in the region, helping to trigger robust counter-pressure by President Truman.⁸

      How the main target lists for sigint were drawn up was of central importance. In theory, they were created by the JIC. However, much of the preliminary work was undertaken by more shadowy committees working under the London Signals Intelligence Board, Britain’s supreme sigint authority. These enjoyed strong military input. When diplomats complained that political and colonial subjects were not getting enough attention, they did not get an enthusiastic response. Many felt that undue weight was being given to defence priorities, and to nuclear warfare in particular. The overwhelming emphasis given to defence had profound implications for the shape of British sigint. It accelerated the development of a revolutionary new kind of sigint that focused on equipment and military formations.⁹

      During the Second World War, Bletchley Park’s primary emphasis had been the interception of communications signals for intelligence purposes. However, as the war progressed, there was growing interest in another kind of sigint that was derived from intercepting electronic signals, such as radar, which had been developed during the Second World War. A related field of interest was the growing use of radio waves to create missile guidance systems. Examining these enemy radio signals was known as electronic intelligence, or ‘elint’. Elint revealed a great deal about enemy weapons, and was also essential for conducting ‘radio warfare’, which involved jamming enemy signals and radar. The first example of this had been the successful efforts of Professor R.V. Jones to divert the beams used to guide the German bombers attacking London. These techniques were refined during the war against Japan. An elaborate elint unit was set up within Mountbatten’s South-East Asia Command under the improbable cover name of the ‘Noise Investigation Bureau’. In the summer of 1945, elint-equipped aircraft called ‘ferrets’ patrolled the night skies over Rangoon listening to Japanese radar.¹⁰ Elint and radio countermeasures, conducted jointly by GCHQ and special units of the RAF, were a massive growth area after 1945, partly because they were so closely linked to strategic weapons. One great advantage of elint was that it rarely required the reading of complex enemy codes.¹¹ Increasingly, the business of signals intelligence would consist of two branches, the familiar one of communications intelligence or ‘comint’ and the new one of elint.

      Britain had excelled in the use of both comint and elint during the Battle of Britain, and later in bombing raids over Germany. One of the architects of this system was Arthur ‘Bill’ Bonsall, who would become Director of GCHQ in 1973.¹² This success had made a deep impression on American intelligence officers in Europe, who felt admiration and not a little envy¹³ In early February 1945, the US Army Air Force held a conference of all senior air intelligence officers (A-2s) across Europe, at which ‘every A-2 expressed his disappointment at our utter dependence on the R.A.F’ in sigint matters. The US Ninth Air Force had deployed some very effective converted Flying Fortresses as airborne listening stations, but the British had controlled the flow of strategic sigint. The lesson was clear. Colonel Robert D. Hughes, Director of Intelligence for the Ninth Air Force, told Washington that he wanted his own air sigint units with control over sigint policy and sigint research: ‘We feel that you should demand, and organize under your control, for peace as well as war, an organization similar to that of the R.A.F…Unlike other highly technical forms of intelligence, in which our American Air Forces have shared, we have continued to depend entirely on the R.A.F. for this level of work in “Y”.’¹⁴

      Elint formed one of the closest parts of the Anglo-American sigint relationship during the immediate post-war period because it focused on the Soviet military target. Exchange on elint was not initially linked to the Allied sigint agreements reached at the end of the war, but in 1948 it was being brought within the growing body of Western intelligence pacts that formed UKUSA. GCHQ approached Washington with a proposal to ‘extend the present British-US Comint collaboration to include countermeasures, intercept activities and intelligence’ in the field of elint. This meant coordinated patterns of ‘ferret’ flights – effectively a division of labour – with the resulting intelligence being swapped ‘via Comint channels’.¹⁵ By the 1950s, GCHQ had achieved control over elint in Britain, and so was managing relations with all the various American outfits in this field. This had meant redrawing GCHQ’s charter to include not only comint but also elint, something which had not pleased everyone. R.V. Jones, who was Director of Scientific Intelligence at the Ministry of Defence in the early 1950s, strongly resented losing this part of his empire; the benefits of having all activities superintended by GCHQ were nevertheless overwhelming.¹⁶

      Anglo-American sharing was important, because elint was an expensive business. Many of the target Soviet signals were short-range and could only be collected from ‘ferrets’, which were effectively flying intelligence stations. Initially, the RAF was ahead in this new field. By 1947 a fleet of specially equipped Lancaster and Lincoln aircraft patrolled the East German border, monitoring Soviet air activity. This was complemented by ground stations at locations