Blue Steel was a British stand-off nuclear medium-range ballistic missile. Developed from 1954 it was operational from February 1963 to 1969. It was 10 meters (35 feet) long with a wingspan of 4 meters (13 feet), an weight of 7000 kilograms (15,000 pounds) and a range of about 240 kilometers (150 miles). The engine was a two-chamber rocket engine using hydrogen peroxide and kerosene. The warhead was a Red Snow one-megaton device.
It was air-launched by aircraft of the V bomber force. On launch the rocket engine's first chamber would power the missile along a predetermined course to the target at araound Mach 1.5. Once close to the target the second chamber of the engine would accelerate the missile to Mach 3, over the target the engine would cut and the missile would free-fall before detonating its warhead as a air-burst.
A replacement for Blue Steel, the Mark 2, was planned with increased range and a ramjet engine. but this was cancelled due to difficulties in developing Mark 1.
The short range of the missile meant that the V bombers were still vulnerable to enemy SAMs. There were a number of attmepts to develop or acquire replacements -- Blue Streak missile and Skybolt ALBM being the two obvious failures.