The Sea Vixen had the distinction of being the first British two-seat combat aircraft to achieve supersonic speed, albeit not in level flight.

In 1946, the de Havilland Aircraft Company conducted discussions with the British Admiralty on its requirements for a future jet-powered all-weather, radar-equipped fighter.

[1] From these talks, it became clear that the aircraft would need a crew of two to handle its radar and navigation equipment, as well as to fly the fighter, and that two engines were required for a safety factor over the ocean, and that swept wings were desirable.

[1] The DH 110 was to be powered by a pair of Rolls-Royce Avon turbojet engines, each capable of generating 7,500 lbf (33 kN) of thrust, which would allow the aircraft to become supersonic in a shallow dive.

To this end the prototypes required would be three for F.4/48, four for common RAF and RN development, and two each for the other three roles and by July the authorities were ready to order the 13 prototypes [6] In 1949, however, the Royal Navy decided to procure the de Havilland Sea Venom which, as a development of an existing aircraft, was cheaper, and would be available sooner to meet its immediate needs for a jet-powered night fighter to replace its fleet of piston-engined de Havilland Sea Hornets and Vought F4U Corsairs.

[1][7] On 26 September 1951, an initial prototype was completed and conducted its maiden flight from the Hatfield Aerodrome, flown by the test pilot John Cunningham.

[9] Following a demonstration of its ability to break the sound barrier during a low level flight, the aircraft disintegrated and debris landed in the midst of spectators killing 31 people, including the crew of two, the test pilot John Derry and his flight-test observer, Tony Richards.

[9][10] Subsequent investigation of the accident traced the failure to faulty design of the wing leading edge section ahead of the main spar.

The design had been satisfactory for the earlier Vampire and Venom but not for the higher stresses induced by the rolling pull-out manoeuvre at 650 mph flown by the DH110 prototype at Farnborough.

The leading edge skin, without the extra reinforcing structure that would be added later, buckled, which resulted in the outer portions of the swept-back wings being torn off (similar display routines had been flown on preceding days by the other prototype DH110 which had an aerodynamic fence providing external stiffening for the skin located precisely over the area where the buckling originated.[11]).

The subsequent shift in the DH 110's centre of pressure caused the aircraft to pitch up, the cockpit and tail sections breaking away and the engines being torn from the airframe by the g loading.

[13] As a result of these changes the DH 110 was no longer able to exceed the speed of sound, only reaching Mach 0.95 in a steep dive where its controls were immovable until passing 10,000 feet (3,000 m).

[17] In addition to tailoring the aircraft for carrier-based operation by the Royal Navy, de Havilland implemented major changes to the Sea Vixen during its redesign.

[1] Throughout the 1950s, when the DH 110 design was still being evolved, major advances had occurred in subsystems such as weaponry, fire-control system, radar equipment, and cockpit instrumentation.

[21] Production Sea Vixens were manufactured at first by de Havilland at its former World War II Airspeed Ltd. "shadow factory" at Christchurch near Bournemouth, starting in March 1957.

The de Havilland Sea Vixen was a jet-powered fleet defence fighter, equipped with a modern radar and air-to-air missiles for its primary role.

[26] The Sea Vixen FAW.1 was cleared to carry the Red Beard free-fall nuclear bomb in the event of an "extreme operational emergency".

[27] The Sea Vixen was powered by a pair of Rolls-Royce Avon 208 turbojet engines and could reach a maximum speed of 690 mph (1,110 km/h) and a range of up to 600 mi (970 km).

[3][31] Both positions were fitted with fully automated height adjustable Martin-Baker Mk.4 ejector seats, which were capable of being deployed under a range of conditions and circumstances, including the aircraft being submerged in water.

In response to Kuwait's appeal for external help, the United Kingdom dispatched a number of ships to the region, including two fleet carriers.

Sea Vixens aboard the fleet carriers flew patrols in the region, and Kassem's aggressive actions wilted in the face of the strong naval presence, thus averting a war over Kuwait.

The Sea Vixens, flying off Centaur, performed a number of duties including the providing of cover for the Royal Marines who were landed in Tanganyika by helicopters.

Later in 1964, HMS Centaur's 892 Squadron Sea Vixens stationed off Indonesia, helped to prevent an escalation of President Sukarno's Indonesia–Malaysia confrontation.

[34] Sea Vixens saw further service during the 1960s, performing duties on Beira Patrol, a Royal Navy operation designed to prevent oil reaching landlocked Rhodesia via the then Portuguese colony of Mozambique.

The Sea Vixen's tactics against faster supersonic fighters such as the BAC Lightning and the Dassault Mirage III was to keep turning until its opponents went low on fuel and then catch them with the Red Top when they tried to break away using afterburner.

[35] The Sea Vixen also flew in an aerobatic role, performing in two Royal Navy display teams: Simon's Sircus and Fred's Five.

Formerly owned and operated by De Havilland Aviation, G-CVIX could be viewed at their hangar at Bournemouth Airport in Dorset and at air shows around the UK.