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
British Aerospace Sea Harrier and were inducted the same year. Ten more Sea Harriers were purchased in November 1985; eventually a total of 30 Harriers were procured, 25 for operational use and the remainder as dual-seat trainer aircraft. Until the 1990s, significant portions of pilot training was carried out in Britain due to limited aircraft availability. The introduction of the Sea Harrier allowed for the retirement of India's previous carrier fighter aircraft, the Hawker Sea Hawk, as well as for the Navy's aircraft carrier, INS "Vikrant" (ex-HMS "Hercules"), to be extensively modernised between 1987 and 1989. India has operated Sea Harriers from both the