Editing Hawker Siddeley Harrier (section)

===P.1154===
{{main|Hawker Siddeley P.1154}}

At the time of the development of the P.1127 Hawker and Bristol had also undertaken considerable development work on a [[supersonic]] version, the Hawker Siddeley P.1154, to meet a [[North Atlantic Treaty Organization]] (NATO) requirement issued for such an aircraft.<ref name= Jefford_12>Jefford 2006, p.&nbsp;12.</ref> The design used a single [[Bristol Siddeley BS100]] engine with four swivelling nozzles, in a fashion similar to the P.1127, and required the use of [[afterburner|plenum chamber burning]] (PCB) to achieve supersonic speeds.<ref name= 'buttler 119-120'>Buttler 2000, pp. 119–120.</ref> The P.1154 won the competition to meet the requirement against strong competition from other aircraft manufacturers such as [[Dassault Aviation]]'s [[Dassault Mirage IIIV|Mirage IIIV]]. The French government did not accept the decision and withdrew; the NATO requirement was cancelled shortly after in 1965.<ref name= Jefford_12-13>Jefford 2006, pp.&nbsp;12–13.</ref>{{refn|The Mirage IIIV had been rejected mainly because of its excessive complexity, using nine engines compared with the P.1154's single-engine approach.<ref name= Jefford_19>Jefford 2006, p.&nbsp;19.</ref>|group=N}}

The Royal Air Force and the Royal Navy planned to develop and introduce the supersonic P.1154 independently of the cancelled NATO requirement. This ambition was complicated by the conflicting requirements between the two services—while the RAF wanted a low-level supersonic strike aircraft, the Navy sought a twin-engine [[air defence]] fighter.<ref name= Jefford_13>Jefford 2006, p.&nbsp;13.</ref> Following the election of the Labour Government of 1964 the P.1154 was cancelled, as the Royal Navy had already begun procurement of the [[McDonnell Douglas F-4 Phantom II|McDonnell Douglas Phantom II]] and the RAF placed a greater importance on the [[BAC TSR-2]]'s ongoing development.<ref name= Jefford_13/> Work continued on elements of the project, such as a supersonic PCB-equipped Pegasus engine, with the intention of developing a future Harrier variant for the decades following cancellation.<ref>Moxton 1982, p.&nbsp;1633.</ref>{{refn|The supersonic Harrier is not to be confused with the Big Wing Harrier. Neither concept would result in a successor aircraft.<ref>Moxton 1982, p.&nbsp;1635.</ref>|group=N}}