In November 1944, the Joint Technical Warfare Committee, along with a separate committee chaired by Sir Henry Tizard, examined the future potential of "weapons of war" and the accompanying Tizard Report published on 3 July 1945 made specific policy directions for the Royal Air Force (RAF) Bomber Command. After the Second World War, the policy of using heavy four-engined bombers for massed raids continued into the immediate postwar period; the Avro Lincoln, an updated version of the Avro Lancaster, became the RAF's standard bomber. In 1946, the Air Staff issued Operational Requirements OR229 and OR230 for the development of turbojet-powered heavy bombers capable of carrying nuclear weapons at high altitude and speed, without defensive armament, to act as a deterrent to hostile powers and, if deterrence failed, to perform a nuclear strike. In conjunction with this ambition, Britain set about developing its own atomic weapons.