The Gen 75 Committee was a committee of the British cabinet, convened by the Prime Minister, Clement Attlee, on 10 August 1945. It was one of many ad hoc cabinet committees, each of which was convened to handle a single issue, and given a prefix of Gen (for general) and a number. The purpose of the Gen 75 committee was to discuss and establish the British government's nuclear policy. Attlee dubbed it the "Atom Bomb Committee". It was replaced by an official ministerial committee, the Atomic Energy Committee, in February 1947. Matters considered by the Gen 75 Committee included decisions on what production facilities should be built to produce nuclear weapons, authorising the construction of nuclear reactors to produce plutonium at Windscale, and a gaseous diffusion plant to produce uranium-235 at Capenhurst. It took decisions on the administrative structures that would oversee production, and appointed Marshal of the Royal Air Force Lord Portal, the wartime Chief of the Air Staff, to run the project, which became High Explosive Research. The final decision to proceed with building nuclear weapons, however, was made by another Gen committee, the Gen 163 Committee. Background During the early part of the Second World War, Britain had a nuclear weapons project, codenamed Tube Alloys. A directorate of that name coordinated this effort. Sir John Anderson, the Lord President of the Council, was the minister responsible, and Wallace Akers from Imperial Chemical Industries (ICI) was appointed the director. At the Quadrant Conference in August 1943, the Prime Minister, Winston Churchill and the President of the United States, Franklin Roosevelt, signed the Quebec Agreement, which merged Tube Alloys with the American Manhattan Project to create a combined British, American and Canadian project. 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. Margaret Gowing noted that the "idea of the independent deterrent was already well entrenched." Many of Britain's top scientists participated in the British contribution to the Manhattan Project. A British mission led by Akers assisted in the development of gaseous diffusion technology at the SAM Laboratories in New York. Another, led by Mark Oliphant, who acted as deputy director at the Berkeley Radiation Laboratory, assisted with the electromagnetic separation process. John Cockcroft became the director