The Hawker P.1103 was a design by Hawker Aircraft

Hawker Aircraft

Hawker Aircraft Limited was a British aircraft manufacturer responsible for some of the most famous products in British aviation history.-History:...

 to meet the British Operational Requirement F.155

Operational Requirement F.155

Operational Requirement F.155 was a specification issued by the British Ministry of Supply for an interceptor aircraft to defend the United Kingdom from high-flying supersonic bombers....

; it was not developed into an aircraft.

Background

Operational Requirement F.155 was a Operational Requirement

Operational Requirement

An Operational Requirement or was a UK Air Ministry document setting out the required characteristics for a future military aircraft or weapon system....

 issued by the British Ministry of Supply

Ministry of Supply

The Ministry of Supply was a department of the UK Government formed in 1939 to co-ordinate the supply of equipment to all three British armed forces, headed by the Minister of Supply. There was, however, a separate ministry responsible for aircraft production and the Admiralty retained...

 in 1955 for an interceptor aircraft to defend the United Kingdom from high flying supersonic bombers.

F.155 specified exacting demands:

• The capability of making an intercept within 20 minutes of target contact (250 miles from the UK) with a target speed of Mach 1+
• Ceiling: 60,000 ft (18,000 m)
• Armament: a mixture of infra-red guided missiles and radar guided missiles
• Crew: A crew of two was specified because of the anticipated workload: pilot plus weapons systems operator (WSO)/navigator

The Ministry of Supply made clear in the requirement that the plane and missiles should be treated as a "weapon system" i.e., a cohesive whole. The armament specifications were covered by a separate Operational Requirement, OR.1131, which listed two missile systems: the infra-red guided de Havilland "Blue Vesta" and the radar-guided Vickers "Red Hebe".

Hawker P1103

The submission by Hawker Siddeley a design by the legendary designer Sir Sydney Camm was effectively a supersonic development of his successful Hawker Hunter

Hawker Hunter

The Hawker Hunter is a subsonic British jet aircraft developed in the 1950s. The single-seat Hunter entered service as a manoeuvrable fighter aircraft, and later operated in fighter-bomber and reconnaissance roles in numerous conflicts. Two-seat variants remained in use for training and secondary...

 design, using a single engine - a 25,000 lb development of the de Havilland Gyron

De Havilland Gyron

|-See also:-Bibliography:* Gunston, Bill. World Encyclopedia of Aero Engines. Cambridge, England. Patrick Stephens Limited, 1989. ISBN 1-85260-163-9-External links:** - A 1957 Flight magazine article on the Gyron...

 breathing through an under-chin air intake. Two detachable rocket boosters, to give a 3.7 minute boost, were carried in midwing nacelles.

1957 Defence White Paper

Although a nuclear threat from high-flying Soviet supersonic nuclear-armed bombers was identified in 1955, F.155 calling for supersonic interceptors (in service by 1962) was superseded by the 1957 Defence White Paper

1957 Defence White Paper

The 1957 White Paper on Defence was a British white paper setting forth the perceived future of the British military. It had profound effects on all aspects of the defence industry but probably the most affected was the British aircraft industry...

. The paper was a major review of military spending and one of its elements was the cancellation of nearly all manned fighter projects as a radical change had occurred in strategic threats with the expectation that intercontinental ballistic missiles and low-level strike would replace high flying bombers.