Hawker Siddeley Harrier cancelled after the release of the British Government's 1957 Defence White Paper, which advocated a policy shift away from manned aircraft and towards missiles. This policy resulted in the termination of the majority of aircraft development projects then underway for the British military. Hawker sought to quickly move on to a new project and became interested in Vertical Take Off/Landing (VTOL) aircraft, which did not need runways. According to Air Chief Marshal Sir Patrick Hine this interest may have been stimulated by the presence of Air Staff Requirement 345, which sought a V/STOL ground attack fighter for the Royal Air
Supermarine Type 324 Supermarine Type 324 The Supermarine Type 324 and Type 325 were British two-engined fighter designs proposed as the replacement for the Supermarine Spitfire and Hawker Hurricane. Neither of them nor a revised design - the Type 327 - to carry cannon was accepted for development and production. As an aircraft to succeed the Hurricane and Spitfire then entering service, Air Ministry specification F.18/37 required a 400+ mph (at 15,000 ft) fighter with twelve .303 inch machine gun armament. Hawker Aircraft submitted a single seat, single engine design with two possible engines, the Hawker Tornado powered by the Rolls-Royce Vulture and