[N 1] In late 1964 a repair programme was underway, but a change of Government led to the new Minister of Defence Denis Healey deciding that the Valiant should be retired from service, and this happened in early 1965.

[4] In January 1947, the British Air Ministry issued Specification B.35/46 for an advanced jet bomber intended to carry nuclear weapons and to fly near the speed of sound at altitudes of 50,000 ft (15,000 m).

[6] While Short Brothers submitted a design, by Geoffrey T. R. Hill,[7] that was judged too ambitious, the Air Staff accepted another submission from the company for a separate requirement, B.14/46, as "insurance" in case the advanced B.35/46 effort ran into trouble.

Aviation authors Bill Gunston and Peter Gilchrist described Specification B.14/46 as "calling for little more than a traditional aircraft fitted with jet engines"[8] Short submitted a conservative design to meet B.14/46, which became the S.A.4 Sperrin.

[10] The proposed design submitted by Vickers was relatively straightforward, being less aerodynamically advanced in comparison to competing bids made by rival firms.

He resisted being pushed to try to more closely match the Victor and Vulcan height and speed requirements or to change equipment from that originally specified as these distractions would jeopardize his promised delivery dates.

[13] Although developing three different aircraft types in response to a single Operational Requirement (OR) was costly, events such as the Berlin Blockade had led to a sense of urgency in providing a deterrent to the Soviet Union from possible acts of aggression in Western Europe.

Testing included engine shutdowns and re-lights,[21] one of which caused a fire in the starboard wing; most of the crew managed to escape the aircraft safely, except for the co-pilot, who struck the tail after ejecting.

Although the Valiant B.2 low-level capabilities were significant, the programme was terminated because the World War 2 "Pathfinder concept" was considered obsolete in the nuclear era.

[32] The B.2 prototype was used for tests for a few years, including the clearance of rocket-assisted take-offs, for the Valiant B.1 at hot or high airfields, using two Super-Sprite rocket motors.

Due to shortages of steel and other materials while setting up an assembly line at Brooklands, substantial portions of the production jigs for the Valiant were made from concrete.

Several Valiants were also used for testing and development purposes, such as its use as a flying testbed during trials of the Blue Steel nuclear-armed standoff missile, which was later added to the arsenal of munitions the other V-bombers were equipped with.

[4] In 1962 the Valiant bomber squadrons were switched to a low-level flight profile in order to avoid enemy Surface-to-Air (SAM) defence systems.

Vic Flintham observed that: "There is a fine irony to the situation, for Vickers had produced the Type 673 B Mk 2 version designed as a fast, low-level pathfinder...

[47] For required takeoff performance from short tropical dispersal bases,[57] a jettisonable rocket booster engines pack was developed for the Valiant.

[60] The crew was reduced to five with the deleted requirement for defensive gun turrets and air gunners, an operational philosophy proved by the De Havilland Mosquito bomber of World War II.

[52][N 3] The pilot and copilot were provided with Martin-Baker Mk.3 ejector seats, while the rear crew had to bail out of the oval main entrance door on the port side of the fuselage.

[45] The fuselage area behind the pressurised crew section and forward of the wing was used to house much of the avionics, and air conditioning equipment, and was sometimes called the "organ loft".

Each of the main gears were equipped with multipad anti-skid disc brakes, and were telescopically linked so that a single drive motor could pull them up into the wing recesses.

[56] The tail, which was attached to the rear fuselage was tapered rather than swept back,[45] the horizontal tailplane was mounted well up the vertical fin to keep it clear of the engines' exhaust.

In 1956, a publication within the Journal of the Institute of Metals[71][N 4] condemned the material DTD683 as being unstable and capable of catastrophic failure when stressing the airframe close to its design limits.

The "Safe-Life" design strategy was dismissed by a Lockheed engineer in a talk given to the Royal Aeronautical Society in 1956, because it did not guarantee safety from catastrophic failure.

[81] On 15 May 1957, a Valiant B(K).1 (XD818) piloted by Kenneth Hubbard dropped the first British hydrogen bomb, the Short Granite, over the Pacific as part of Operation Grapple.

[82] No 49 Squadron was selected to perform the live weapon drop, and were equipped with specially-modified Valiants to conform with the scientific requirements of the tests and other precautionary measures to protect against heat and radiation.

[74] Originally the bombing role was to have been carried out at high altitude, but following the shooting down in 1960 of the Lockheed U-2 flown by Gary Powers by an early Soviet SA-2 Guideline missile, the SAM threat caused bomber squadrons to train for low-level attack as a means of avoiding radar detection when flying within hostile airspace.

The HDU was mounted on bomb-mounting points and could be removed if necessary; this arrangement meant that the bomb bay doors had to be opened in order to transfer fuel to a receiver aircraft.

These aircraft were ultimately fitted with American APT-16A and ALT-7 jamming transmitters, Airborne Cigar and Carpet jammers, APR-4 and APR-9 "sniffing" receivers, and chaff dispensers.

Several modifications to the aircraft were made, including a metal radome, debris guards on the two inboard engines, and after six flights the aileron and elevator artificial feel was reduced by 50%.

[102] This was followed on 6 August by a failure of the starboard wing rear spar at 30,000 ft,[103] in WP217, an OCU aircraft from Gaydon captained by Flight Lieutenant "Taffy" Foreman.

[112] On 9 December 1964, the last Valiant tanker sortie in XD812 of 214 Squadron was refuelling Lightning aircraft over the North Sea and was recalled to land back at Marham before the scheduled exercise was completed.