Operational Requirement F.155 was an Operational Requirement issued by the British Ministry of Supply 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 weapon 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".

The submission by Hawker Siddeley a design by the legendary designer Sir Sydney Camm was effectively a supersonic development of his successful Hawker Hunter design, using a single engine - a 25,000 lb  development of the de Havilland Gyron breathing through an under-chin air intake.
Two detachable rocket boosters, to give a 3.7 minute boost, were carried in mid-wing nacelles.
Operational Requirement F.155 was an Operational Requirement issued by the British Ministry of Supply 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 weapon 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".
The submission by Hawker Siddeley a design by the legendary designer Sir Sydney Camm was effectively a supersonic development of his successful Hawker Hunter design, using a single engine - a 25,000 lb  development of the de Havilland Gyron breathing through an under-chin air intake. Two detachable rocket boosters, to give a 3.7 minute boost, were carried in mid-wing nacelles.
Hawker P.1103