Hawker Siddeley P.1127 GR.1" designation. The Harrier went on to become a successful aircraft in British service, and was exported to several nations, often seeing usage as a carrier-based aircraft. The P.1127/Kestrel was an experimental V/STOL aircraft, which served as the forerunner for the production of the Hawker Siddeley Harrier and the wider Harrier Jump Jet family. It served to demonstrate an entirely original technique of flight, as well as to trial a brand new type of engine in the form of the Pegasus turbofan engine. Despite this, the aircraft employed a principally conventional structure which, according to Mason, lent itself favourably to
Hawker Siddeley Harrier designated "P.1127 (RAF)", of which the first made its maiden flight on 31 August 1966. An order for 60 production aircraft, designated as Harrier GR.1, was received in early 1967. The aircraft was named after the Harrier, a small bird of prey. The Harrier GR.1 made its first flight on 28 December 1967. It officially entered service with the RAF on 18 April 1969 when the Harrier Conversion Unit at RAF Wittering received its first aircraft. The aircraft were built in two factories—one in Kingston upon Thames, southwest London, and the other at Dunsfold Aerodrome, Surrey—and underwent initial testing at