On this day in 1957, a four-engined jet Valiant of No 49 Squadron RAF Bomber Command, normally based in Wittering, Northants, flew over the Pacific and exploded Britain's first H-Bomb. The test was carried out at high altitude over the largely uninhabited Christmas Island (pictured right) to minimise nuclear fall-out. Details of the mission, was announced by the Ministry Of Supply. Described only as a 'nuclear device' details of the bomb were described as sketchy. Britain began its thermo-nuclear weapons programme in December 1954 to develop the megaton hydrogen bomb, which is as powerful as one million tons of TNT. Scientists had taken only two years to develop the tests compared with their American counterparts who took seven years to explode their first device.
The tests raised a major debate about the dangers of nuclear weapons and led to the founding in 1958 of the Campaign for Nuclear Disarmament which pressed for British, and ultimately international, abandonment of nuclear weapons.
The Cold War and the arms race between the superpowers reached its peak by the 1960s. Then relations thawed and in 1963 the Soviet Union, the UK, and the USA and many other countries agreed to a Nuclear Test Ban Treaty.