British Defense Policy and the Atomic Bomb at the Dawn of the Cold War, 1945–52

Matthew Jones
Department of International History, London School of Economics and Political Science, London, U.K.

At the end of the Second World War Britain had emerged alongside the United States and Soviet Union as one of the victorious "Big Three" but with her global power and economic base much weakened. Already wary of postwar Soviet intentions in Europe, British defense planners faced an almost overwhelming set of challenges as, amongst other things, they sought to re-establish colonial control in South East Asia, maintain a precarious position in the Middle East and eastern Mediterranean, and provide occupation forces for a defeated Germany. They also had to manage the transition to a much smaller scale of defense effort, as demobilization of the armed forces and major reductions in military spending occurred with the transition to peacetime conditions. An important effect of the British experience of being subject to German bombing during the Second World War, moreover, was to intensify deep-rooted feelings of geographical and physical vulnerability to direct aerial attack. The loss of sixty thousand civilian lives, destruction of housing stock, and disruption to industry had been met with considerable resilience, fortitude, and flexibility. But to postwar British chiefs it was obvious that if another hostile power were to gain control of airbases on Continental Europe from which long-range aircraft could operate, the scale of bombardment which could be inflicted on the home islands might prove to be far more damaging. The advent of the atomic bomb, given graphic expression by its decisive use against the Japanese cities of Hiroshima and Nagasaki in August 1945, made it even more apparent that a hostile power could even threaten national survival. Compounding Britain's dilemmas was that the United States was not yet committed to the defense of Western Europe against the Soviet threat that many now discerned, with U.S. forces rapidly demobilizing and returning home.

British defense chiefs reached the early conclusion that a policy of deterrence by the threat of retaliation, through accumulation of a sufficient stock of atomic bombs and their means of effective delivery, was the best means to prevent an atomic attack against the United Kingdom base. In a report issued in mid-June 1945, for example, an ad hoc scientific committee examining future technical developments in warfare for the Chiefs of Staff (COS), led by the eminent defense scientist Sir Henry Tizard, advocated a postwar program of research into atomic energy. The Committee's report concluded that the

only answer that we can see to the atomic bomb is to be prepared to use it ourselves in retaliation. A knowledge that we were prepared, in the last resort, to do this might well deter an aggressive nation. Duelling was a recognised method of settling quarrels between men of high social standing so long as the duellists stood twenty paces apart and fired at each other with pistols of a primitive type. If the rule had been that they should stand a yard apart with pistols at each other's hearts, we doubt whether it would long have remained a recognised method of settling affairs of honour.[1]

The new Prime Minister, Clement Attlee, had also been quick to appreciate the changed circumstances brought by the arrival of the atomic bomb. In a memorandum composed in August 1945 he argued that previous ideas about postwar military planning, for example the need to disperse essential industries to make them less susceptible to aerial bombardment, had been rendered "quite futile" as nothing could "alter the fact that the geographical situation of Britain offers to a Continental Power such targets as London and the other great cities." Measures of civil defense were also likely to prove a,

futile waste… the modern conception of war to which in my lifetime we have become accustomed is now completely out of date. We recognized or some of us did before this war that bombing could only be answered by counter bombing. We were right. Berlin and Magdeburg were the only answer to London and Coventry. Both derive from Guernica. The answer to an atomic bomb on London is an atomic bomb on another great city.[2]

In October 1945, the COS offered their own opinion that in the absence of international controls over atomic weapons, possession of the bomb would be vital to postwar security, and, as Attlee was informed by the Secretary of the COS Committee (in a paraphrase of its views), "the best method of defence against the new weapon is likely to be the deterrent effect that the possession of the means of retaliation would have on a potential aggressor." Atomic research leading, as soon as possible, to the development and production of the weapons themselves was considered essential, and "To delay production pending the outcome of negotiations regarding international control might well prove fatal to the security of the British Commonwealth."[3] That same month saw the establishment of nuclear research facilities at Harwell in Oxfordshire, and in early 1946 the ground was prepared for the construction of nuclear reactors which could produce the vital fissile material required to manufacture nuclear weapons. Despite the huge expense and major industrial and scientific effort required, British political leaders were resolved that Britain should become a nuclear weapon state. Scientific hubris also played a role: British scientists had played a key role in early research into nuclear physics and had worked alongside the Americans on the Manhattan Project that had produced the first atomic bomb. Postwar research into atomic energy and its military applications was regarded by many as nothing more than a natural progression from what had been achieved during wartime, building on the momentum generated by the mobilization of scientific manpower by government. Britain considered that it was a nuclear pioneer and had every intention of maintaining its knowledge and expertise in this important field.

An Air Staff Operational Requirement for an atomic bomb – reflecting the climate of official opinion as to the necessity of its development – was first issued in August 1946. A few months later the Air Ministry produced a specification for a new high-performance bomber which could carry the weapon when it was finally manufactured.[4] The resulting competition led to contracts for not one, but three different varieties of aircraft, a program which was to reach fruition in the latter half of the 1950s with the entry into service of the famous V-bomber force of Valiants, Victors and Vulcans. How large a nuclear force would be needed – an evaluation which was required as a yardstick for future planning – was a question which, for the moment, defied any ready and obvious answer. Asked for their opinion on the optimum size of a U.K. nuclear stockpile so that production needs for fissile material could be calculated, all the COS could offer, in a paper issued at the beginning of January 1946, was the view that it was "not possible now to assess the precise number which we might require but we are convinced we should aim to have as soon as possible a stock in the order of hundreds rather than scores."[5] In January 1947 a small ad hoc Cabinet Committee, GEN 163, chaired by Attlee took the final decision to develop and manufacture an atomic bomb – in many ways simply ratifying a course of policy already firmly established by the government – and work began in earnest under the auspices of the Ministry of Supply, initially at Fort Halstead in Kent.

By this time all substantive nuclear cooperation with the United States had been terminated after Congress had passed the McMahon Act, designed to preserve the American atomic monopoly, in August 1946. Britain would have to proceed with the nuclear program on the basis of its own resources and knowledge.[6] In a major report on future defense policy produced by the Chiefs of Staff in May 1947, it was admitted that Soviet land forces could easily overrun Western Europe if they chose, putting the United Kingdom within range, once they had been developed, of shorter-range Soviet rockets. When she acquired nuclear weapons, the COS argued, the "only means" whereby their use by the Russians in war might be prevented,

is by facing her with the threat of large-scale damage from similar weapons if she should employ them. This threat can only be achieved by evidence of our ability to use weapons of mass destruction on a considerable scale from the outset. In addition we believe that the knowledge that we possessed weapons of mass destruction and were prepared to use them would be a most effective deterrent to war itself.[7]

Moreover, with the United States in possession of the principal means of Western retaliation to Soviet attack, a British nuclear capability was increasingly seen as essential to give London a voice in U.S. deliberations over the vital matters of war and peace that were bound to take place over the coming years.

In the autumn of 1948 the Joint Intelligence Committee, working alongside the Joint Planning Staff, was asked by the Chiefs of Staff to examine how atomic weapons might best be used in a war against Russia in order to achieve "a rapid and decisive victory." The outbreak of such a war was assumed to occur in 1957, and Allied belligerents would include the UK, USA and other members of the soon to be signed North Atlantic Pact.[8] The resulting report was eventually produced in early August 1949. It presented the argument that "effective atomic attack on all the towns which are centers of control – political, economic and administrative – is the best method of creating conditions in which the functions of Government and of the Soviet Police would break down. This would necessitate attacking about 100 large towns in the Soviet Union; moreover, it would be essential to attack all these centers within as short a period as possible. An additional advantage of such a plan would be that about 15 per cent of the total population of the Soviet Union would either become casualties or be displaced. This might weaken the will of the people to resist. Unless, however, the administration is broken, fear of the Secret Police, the fundamental patriotism of the Soviet people, and their capacity to endure hardships, together with their Communist upbringing, would be sufficient to make the Russian people follow their leaders and support Soviet war policy." To achieve such a large scale attack on Soviet urban areas, it was calculated, would take somewhere between 400 and 575 atomic bombs. "The destruction of these [100] cities would be a national disaster of such magnitude that it might also be expected to shatter the faith of the Russian people in their leaders and would seriously weaken both their will and ability to continue the war."[9]

Within only a few weeks of the production of this report, the Soviet Union would also have the capacity to retaliate against a nuclear attack, or to initiate the use of nuclear weapons. There was a widespread assumption during the Second World War that the Russians had also been busily engaged in nuclear research.[10] The swift breakdown of cooperation with the Soviet Union over the postwar settlement in central and eastern Europe made it essential to know when the Soviet Union could be expected to produce its own atomic bomb and what its rate of annual production was likely to be. In October 1945, the Joint Intelligence Committee had concluded that "atomic developments" were "the paramount potentiality of the future" and that an accurate picture of the Soviet program was crucial.[11] Paucity of reliable intelligence on the Soviet atomic bomb project was a continual problem throughout the period, and as a result estimates of the date for the first Soviet atomic test were inaccurate by some margin. In 1947, for example, it was predicted that the Soviet Union might have an atomic bomb by 1952.[12] By January 1949, the JIC had accepted that this timescale could be reduced but it was still believed that the earliest probable date for a test was in 1953.[13] The considered view of the British intelligence authorities was that the Soviet Union would not risk launching an aggressive war against the West until it had built up an adequate stockpile of atomic bombs, and that such a stockpile would probably not materialize before about 1957. The first Soviet atomic test in August 1949 thus came as a great shock to British defense planners, as did the realization that the Soviet authorities had access to much more extensive supplies of fissile material than had been assumed, allowing them to engage in a more rapid buildup of nuclear weapons. Suddenly, the possibility of war seemed that much closer and the gradual increases in British military strength that had been anticipated by the Chiefs of Staff – including the eventual acquisition of a nuclear capability – no longer looked sufficient or timely. The outbreak of the Korean War in June 1950, where some saw Stalin's hand as lying behind the North Korean attack on the south, confirmed many fears that Moscow was ready for an armed confrontation with the West and set the stage for the Attlee Government's major program of rearmament announced later that same year.

The increase in international tensions that was heralded by the breaking of the U.S. atomic monopoly in 1949 and then the Korean War, which also witnessed the commitment of British forces to the fighting as part of a U.N. effort, only underlined the urgency for Britain of moving forward quickly with its own nuclear program. In April 1950 a site at a former wartime aerodrome at Aldermaston in Berkshire was chosen as the location for the new Atomic Weapons Research Establishment (AWRE). Under the determined direction of Sir William Penney, AWRE embarked upon a major program of research, design, and fabrication, combining British wartime engineering and scientific skills with what knowledge Penney had picked up as a key British member of the U.S. wartime Manhattan Project at Los Alamos. Meanwhile, Britain's fledgling nuclear reactors were busy producing the plutonium that would be required for the first U.K. test, and a test site was prepared off the northwest coast of Australia. The return to office of Winston Churchill as Prime Minister in October 1951 only served to give an even greater spur to the atomic effort, and a year later Operation Hurricane – the first British atomic test – was carried out in the Monte Bello islands. The whole project, it was later estimated, had cost in the region of £150 million, and there was critical comment about the diversion of effort away from the area of conventional forces. But to its supporters the huge venture had been worth such an investment: Britain had become the third member of the nuclear club, its defense chiefs could begin to plan how its own nuclear weapons might be used for the purposes of deterrence, while their political masters anticipated that British influence in Washington would be enhanced. Finally, now that the United States was committed to the defense of Western Europe through NATO, possession of the atomic bomb increasingly became seen as a means to maintain independence from the U.S., whose nuclear strength would otherwise hold the keys to Britain's security.

[1] COS(45)402(O), "Future Developments in Weapons and Methods of War," report by Sir Henry Tizard's "Ad Hoc" Committee, June 16, 1945, DEFE 2/1251, The National Archives (TNA), UK; and see Gowing (1974, 32–33, 163).

[2] GEN 75/1, "The Atomic Bomb," memorandum by the Prime Minister, August 28, 1945, CAB 130/3, TNA, UK.

[3] Major General Leslie C. Hollis minute for Attlee, October 10, 1945, PREM 8/116, and as COS 1449/5 annexed to COS(45)246th mtg, October 10, 1945, CAB 79/40, TNA, UK.

[4] See Gowing (1974, 174, 234) and Wynn (1994, 17–18, 26–27, 44–47).

[5] GEN 75/22, "Large Scale Production of Materials for Use as a Source of Atomic Energy," Note by the Secretary of the Cabinet, January 2, 1946, covering Chiefs of Staff minute for the Prime Minister, January 1, 1946, CAB 130/3, TNA, UK; and see also Gowing (1974, 169) and Wynn (1994, 13).

[6] GEN 163/1st Meeting, Confidential Annex, January 8, 1947, CAB 130/16, TNA, UK;  and for Bevin's views see Bullock (1983, 352).

[7] DO(47)44, "Future Defence Policy", report by the Chiefs of Staff, May 22 ,1947, CAB 131/4, TNA, UK.

[8] JIC(48)116(Terms of Reference), "Defence Aspects of Atomic Energy", November 2 1948, CAB 158/5, TNA, UK.

[9] JIC(48)116(Final), "The Use of Atomic Bombs in a War Against the Soviet Union", August 4 1949, CAB 158/5, TNA, UK.

[10] See, for example, Lewis (2003, 12235, 349–353).

[11]  JIC/1468/45, "Intelligence on Atomic Energy", October 11, 1945, CAB 176/8, TNA, UK.

[12] JIC(47)7/2, "Soviet Interests, Intentions and Capabilities", August 6, 1947, CAB 158/1, TNA, UK.

[13] JIC(49)55(Final), "Soviet Intentions and Capabilities", September 6, 1949 (though written in June 1949), CAB 158/7, TNA, UK.


Bullock, Alan. 1983. Ernest Bevin: Foreign Secretary 1945–1951. Oxford University Press: Oxford.

Gowing, Margaret. 1974. Independence and Deterrence: Britain and Atomic Energy, 1945–1952. Volume 1: Policy Making. Palgrave Macmillan: London.

Lewis, Julian. 2003. Changing Direction: British Military Planning for Post-war Strategic Defence, 1942–1947. 2nd ed. Routledge: Abingdon.

Wynn, Humphrey. 1994. The RAF Nuclear Deterrent Forces: Their Origins, Roles and Deployment 1946–1969. Stationary Office Books: London.

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