Tube Alloys

The Tube Alloys was a codename of the clandestine research and development programme, authorized by the Government of the United Kingdom with participation from Canada, aiming to develop atomic weapons for Great-Britain's nuclear program during World War II. Starting with the Western Allies's nuclear bomb project in 1942, the British efforts were kept in extremely high-level secrecy such that they had to be referred to by code even within the highest circles of government. At the end of World War II, the Tube Alloys came to refer specifically to the element plutonium, whose very existence was secret until its use in the atomic bombing of Nagasaki.

The Tube Alloys programme in Britain and Canada, effectively the first nuclear weapons project of its type, was eventually subsumed into the US-led Manhattan Project. Both programmes had some elements of earlier research accomplished in France and Germany. Despite reaching the understanding with the United States, the details of such efforts weren't completely provided to the United Kingdom, although ironically the Soviet Union gained valuable details, scientific data and research documents through subterfuge critical for the development of nuclear weapons. This prompted the United Kingdom to (re)launch its own directorate to match the achievements of the Soviets and Americans. Production facilities were established under the auspices of the British Army and Royal Air Force and British scientists were re-called from the United States to continue their work under the auspices of an independent British programme. Finally in 1952, Britain performed a test under codename Hurricane, a decade after conducting research on the field. In 1958, after British demonstration of a two-stage thermonuclear (fission-fusion) bomb, the United Kingdom and the United States signed a defence understanding agreement that resulted in the United Kingdom electing to resume its nuclear weapons co-operation with the United States.