The Avro Vulcan, sometimes referred to as the Hawker Siddeley Vulcan, is a delta wing subsonic jet strategic bomber that was operated by the Royal Air Force (RAF) from 1953 until 1984. It was developed by Avro in response to a specification released by the Air Ministry. At the time, both jet engines and delta wings were considered cutting-edge and relatively unexplored; thus, the small-scale Avro 707 was produced to test the principles of the design. In flight, the Vulcan was an agile aircraft for its size. Avro Vulcan XH558 (civil aircraft registration G-VLCN) The Spirit Of Great Britain is the only airworthy example of the 134 Avro Vulcan V-bombers that were operated by the Royal Air Force from 1953 until 1984. Vulcan XH558 served with the RAF between 1960 and 1985 in the bomber, maritime reconnaissance and air-to-air refuelling roles.