In 1957, the Bristol Engine Company informed Hawker chief engineer, Sidney Camm, of an in-house project to develop a vectored thrust fanjet based on their Olympus and Orpheus engines. This new concept was predicated on four separate centrifugal blowers with rotating nozzles to facilitate a hover capability. Hawkers saw the opportunity to use this engine, to be known as the Pegasus, as the power plant for an aircraft to meet the contemporary NATO requirement for a light tactical support fighter. Much initial development funding and modelling was undertaken by the United States and such was the potential that in March 1959 Hawkers decided to fund two P1127 prototypes.
The first of the P1127s was ready for static engine testing in July 1960 and a flight-capable engine was delivered three months later. It was decided to research the unknowns of hovering before flying the machine conventionally and so it was that on 19th October 1960 the first tethered flight took place with chief test pilot Bill Bedford at the controls. The test programme continued with progressively longer tethers being used and on 13th March 1961 the first conventional flight was carried out by way of a horizontal take-off. A second aircraft joined the programme in July 1961 and first transitions from the hover to conventional flight and vice versa were conducted from September of that year. A further four P1127s were ordered, the last of which entered the development programme on 13th February 1964. Eight months later a Tripartite Unit comprising UK, US and German personnel was established to evaluate its successor, the Kestrel, and thereafter the Harrier emerged to enter RAF service in April 1969
Of the six P1127s built, three were lost. Bill Bedford ejected from one in December 1961 when control was lost on the approach to landing after a nozzle detached from the aircraft, whilst a second machine, which crashed at Le Bourget in June 1963, was rebuilt and is now on display at the Science Museum. The third came to grief on 30th October 1962 when Hawker’s deputy chief test pilot Hugh Merewether suffered a catastrophic engine failure and fire over West Sussex. Rather than eject, he managed a high-speed glide landing at RAF Tangmere thereby allowing engineers to investigate the cause. In recognition of this feat, Merewether was awarded the Queen’s Commendation for Valuable Service in the Air.