The UK's first nuclear weapon, Blue Danube, was large and cumbersome, being long and wide, and weighed , so only the Royal Air Force (RAF) V-bombers could carry it. In November 1953, the RAF and Royal Navy issued an Operational Requirement, OR.1127, for a smaller, lighter weapon with similar yield that could be carried by tactical aircraft. A second requirement for a light-weight bomb arose with the British Government's decision in July 1954 to proceed with a British hydrogen bomb programme. Hydrogen bombs required an atomic bomb as a primary, and one was incorporated in the British hydrogen bomb design, known as Green Granite.