The "V bombers" were the Royal Air Force (RAF) aircraft during the 1950s and 1960s that comprised the United Kingdom's strategic nuclear strike force known officially as the V force or Bomber Command Main Force. The three models of strategic bomber, known collectively as the V class, were the Vickers Valiant, which first flew in 1951 and entered service in 1955; the Avro Vulcan, which first flew in 1952 and entered service in 1956; and the Handley Page Victor, which first flew in 1952 and entered service in 1957. The V Bomber force reached its peak in June 1964 with 50 Valiants, 70 Vulcans and 39 Victors in service. When it became clear that the Soviet Union's surface-to-air missiles like the S-75 Dvina could bring down high-flying aircraft, the V bomber force changed to low-level attack methods. Additionally the Blue Steel missile profile was changed to one of low level penetration and release. This reduced its range significantly. It was then planned to move to the much longer-ranged Skybolt air-launched ballistic missile. When the US cancelled Skybolt, the survivability of the V force was highly questionable. This led to the Royal Navy taking over the nuclear deterrent role from 1968, using UGM-27 Polaris submarine launched ballistic missiles launched from nuclear submarines. The tactical role passed to smaller aircraft like the SEPECAT Jaguar and Panavia Tornado. The V bombers were also capable of dropping conventional weapons, supported by a complex analogue computer system known as the Navigation and Bombing System that allowed accurate bombing even over very long ranges. The Valiants were used during the Suez Crisis as conventional bombers. Victors and Vulcans were deployed to the Malay Archipelago as a deterrent during the Indonesia–Malaysia confrontation but were not used in missions. The Vulcan is well-remembered for its conventional Black Buck bombing raids during the 1982 Falklands War. To support such missions, tanker aircraft versions of all three designs were developed. Reconnaissance versions were produced, and other modifications were also made during their lifetime. The Valiants were removed from service in 1964 after problems with metal fatigue of their wings became apparent; a planned low-level variant did not progress beyond the prototype. Usage of all V bombers as weapons platforms, nuclear or conventional, ended in 1982. Background The Royal Air Force (RAF) Bomber Command ended the Second World War with a policy of using heavy four-piston-engined bombers for massed raids, and