High Explosive Research was the British project to develop atomic bombs independently after the Second World War. This decision was taken by a cabinet sub-committee on 8 January 1947, in response to apprehension of an American return to isolationism, fears that Britain might lose its great power status, and the actions by the United States to withdraw unilaterally from sharing of nuclear technology under the 1943 Quebec Agreement. The decision was publicly announced in the House of Commons on 12 May 1948.
This was a civil project, not a military one. Staff were drawn from and recruited into the Civil Service, and were paid Civil Service salaries. It was headed by Lord Portal, as Controller of Production, Atomic Energy, in the Ministry of Supply. An Atomic Energy Research Establishment was located at a former airfield, Harwell, in Berkshire, under the direction of John Cockcroft. The first nuclear reactor in the UK, a small research reactor known as GLEEP, went critical at Harwell on 15 August 1947. British staff at the Montreal Laboratory designed a larger reactor, known as BEPO, which went critical on 5 July 1948. They provided experience and expertise that would later be employed on the larger, production reactors. Production facilities were constructed under the direction of Christopher Hinton, who established his headquarters in a former Royal Ordnance Factory at Risley in Lancashire. These included a uranium metal plant at Springfields, nuclear reactors and a plutonium processing plant at Windscale, and a gaseous diffusion uranium enrichment facility at Capenhurst, near Chester. The two Windscale reactors became operational in October 1950 and June 1951. The gaseous diffusion plant at Capenhurst began producing highly enriched uranium in 1954. William Penney directed bomb design from Fort Halstead. In 1951 his design group moved to a new site at Aldermaston in Berkshire. The first British atomic bomb was successfully tested in Operation Hurricane, during which it was detonated on board the frigate HMS Plym anchored off the Monte Bello Islands in Australia on 3 October 1952. Britain thereby became the third country to test nuclear weapons, after the United States and the Soviet Union. The project concluded with the delivery of the first of its Blue Danube atomic bombs to Bomber Command in November 1953, but British hopes of a renewed nuclear Special Relationship with the United States were frustrated. The technology had been superseded by the American development of the hydrogen bomb, which was first tested in November 1952, only one month after Operation Hurricane. Britain went on to develop its own hydrogen bombs, which it first tested in 1957. A year later, the United States and Britain resumed nuclear weapons cooperation. The neutron was discovered by James Chadwick at the Cavendish Laboratory at the University of Cambridge in February 1932. [1] In April 1932, his Cavendish colleagues John Cockcroft and Ernest Walton split lithium atoms with accelerated protons. [2] Enrico Fermi and his team in Rome conducted experiments involving the bombardment of elements by slow neutrons, which produced heavier elements and isotopes.[3] Then, in December 1938, Otto Hahn and Fritz Strassmann at Hahn's laboratory in Berlin-Dahlem bombarded uranium with slowed neutrons,[4] and discovered that barium had been produced, and therefore that the uranium nucleus had been split.[3] Hahn wrote to his colleague Lise Meitner, who, with her nephew Otto Frisch, developed a theoretical justification for the process, which they published in Nature in 1939.[5] By analogy with the division of biological cells, they named the process "fission".[6] The discovery of fission raised the possibility that an extremely powerful atomic bomb could be created.[7] The term was already familiar to the British public through the writings of H. G. Wells, in his 1913 novel The World Set Free. [8] George Paget Thomson, at Imperial College London, and Mark Oliphant, an Australian physicist at the University of Birmingham, were tasked with carrying out a series of experiments on uranium. By February 1940, Thomson's team had failed to create a chain reaction in natural uranium, and he had decided that it was not worth pursuing;[9] but at Birmingham, Oliphant's team had reached a strikingly different conclusion. Oliphant had delegated the task to two German refugee scientists, Rudolf Peierls and Frisch, who could not work on the university's secret projects like radar because they were enemy aliens and therefore lacked the necessary security clearance.[10] They calculated the critical mass of a metallic sphere of pure uranium-235, and found that instead of tons, as everyone had assumed, as little as 1 to 10 kilograms (2.2 to 22.0 lb) would suffice, which would explode with the power of thousands of tons of dynamite.[11][12][13] Oliphant took the Frisch–Peierls memorandum to Sir Henry Tizard, the chairman of the Tizard Committee,[14] and the MAUD Committee was established to investigate further.[15] It directed an intensive research effort, and in July 1941, produced two comprehensive reports that concluded an atomic bomb was not only technically feasible, but could be produced before the war ended, perhaps in as little as two years. The Committee unanimously recommended pursuing the development of an atomic bomb as a matter of urgency, although it recognised that the resources required might be beyond those available to Britain.[16][17] A new directorate known by the deliberately misleading name of Tube Alloys was created to coordinate this effort. Sir John Anderson, the Lord President of the Council, became the minister responsible, and Wallace Akers from Imperial Chemical Industries (ICI) was appointed the director of Tube Alloys.[18] Manhattan Project Main article: British contribution to the Manhattan Project In July 1940, Britain had offered to give the United States access to its scientific research,[19] and Cockcroft, as part of the Tizard Mission, briefed American scientists on British developments.[20] He discovered that the American project was smaller than the British, and not as far advanced.[16] The British and American projects exchanged information, but did not initially combine their efforts. British officials did not reply to an August 1941 American offer to create a combined project.[21] In November 1941, Frederick L. Hovde, the head of the London liaison office of the American Office of Scientific Research and Development (OSRD), raised the issue of cooperation and exchange of information with Anderson and Lord Cherwell, who demurred, ostensibly over concerns about American security. Ironically, it was the British project that had already been penetrated by atomic spies for the Soviet Union.[22] Groves sits a completely clean desk. Chadwick, seated next to him, looks on. James Chadwick (left), the head of the British Mission, with Major General Leslie R. Groves, Jr., the director of the Manhattan Project. The United Kingdom did not have the manpower or resources of the United States, and despite its early and promising start, Tube Alloys fell behind its American counterpart and was dwarfed by it.[23] On 30 July 1942, Anderson advised the Prime Minister, Winston Churchill, that: "We must face the fact that ... [our] pioneering work ... is a dwindling asset and that, unless we capitalise it quickly, we shall be outstripped. We now have a real contribution to make to a 'merger.' Soon we shall have little or none."[24] The British considered producing an atomic bomb without American help, but the project would have needed overwhelming priority, the projected cost was staggering, disruption to other wartime projects was inevitable, and it was unlikely to be ready in time to affect the outcome of the war in Europe. The unanimous response was that before embarking on this, another effort should be made to secure American cooperation.[25] At the Quadrant Conference in August 1943, Churchill and the American President, Franklin Roosevelt, signed the Quebec Agreement, which merged the two national projects.[26] Its terms made it clear that Britain was the junior partner in the Grand Alliance. The British considered the Quebec Agreement to be the best deal they could have struck under the circumstances, and the restrictions were the price they had to pay to obtain the technical information needed for a successful post-war nuclear weapons project.[27] Margaret Gowing noted that the "idea of the independent deterrent was already well entrenched."[28] The Quebec Agreement established the Combined Policy Committee and the Combined Development Trust to coordinate their efforts.[29] The 19 September 1944 Hyde Park Aide-Mémoire extended both commercial and military cooperation into the post-war period.[30] A British mission led by Akers assisted in the development of gaseous diffusion technology at the SAM Laboratories in New York.[31] Another, led by Oliphant, who acted as deputy director at the Berkeley Radiation Laboratory, assisted with the electromagnetic separation process.[32] Cockcroft became the director of the Anglo-Canadian Montreal Laboratory.[33] The British mission to the Los Alamos Laboratory led by James Chadwick, and later Peierls, included distinguished scientists such as Geoffrey Taylor, James Tuck, Niels Bohr, William Penney, Frisch, Ernest Titterton and Klaus Fuchs, who was later revealed to be a Soviet spy.[34][35] As overall head of the British Mission, Chadwick forged a close and successful partnership with Brigadier General Leslie R. Groves, the director of the Manhattan Project. [36] He ensured that British participation was complete and wholehearted.[37] End of American cooperation With the end of the war the Special Relationship between Britain and the United States "became very much less special". [38] The British government had trusted that America would share nuclear technology, which it considered a joint discovery.[39] On 8 August 1945 the Prime Minister, Clement Attlee, sent a message to President Harry Truman in which he referred to themselves as "heads of the Governments which have control of this great force".[39] Roosevelt had died on 12 April 1945, and the Hyde Park Aide-Mémoire was not binding on subsequent administrations.[40] In fact, the American copy was temporarily physically lost. When Field Marshal Henry Maitland Wilson raised the matter in a Combined Policy Committee meeting in June, the American copy could not be found.[41] The British sent Secretary of War, Henry L. Stimson a photocopy on 18 July 1945.[40] Even then, Groves questioned the document's authenticity until the American copy was located years later in the papers of Vice Admiral Wilson Brown, Jr., Roosevelt's naval aide, apparently misfiled by someone unaware of what Tube Alloys was, and thought it had something to do with naval guns.[41][42][43] On 9 November 1945, Attlee and the Prime Minister of Canada, Mackenzie King, went to Washington, D.C., to confer with Truman about future cooperation in nuclear weapons and nuclear power.[44][45] A Memorandum of Intention they signed replaced the Quebec Agreement. It made Canada a full partner; continued the Combined Policy Committee and Combined Development Trust; and reduced the obligation to obtain consent for the use of nuclear weapons to merely requiring consultation.[46] The three leaders agreed that there would be full and effective cooperation on atomic energy, but British hopes for a resumption of cooperation on nuclear energy were disappointed.[47] The Americans soon made it clear that cooperation was restricted to basic scientific research.[48] The next meeting of the Combined Policy Committee on 15 April 1946 produced no accord on collaboration, and resulted in an exchange of cables between Truman and Attlee. Truman cabled on 20 April that he did not see the communiqué he had signed as obligating the United States to assist Britain in designing, constructing and operating an atomic energy plant. [49] The passing of the Atomic Energy Act of 1946 (McMahon Act) in August 1946, which was signed by Truman on 1 August 1946, and went into effect at midnight on 1 January 1947,[50] ended technical cooperation. Its control of "restricted data" prevented the United States' allies from receiving any information.[51] This partly resulted from the arrest for espionage of British physicist Alan Nunn May, who had worked in the Montreal Laboratory, in February 1946, while the legislation was being debated.[52] The remaining British scientists working in the United States were denied access to papers that they had written just days before.[53]