Editing Vickers Valiant (section)

===Nuclear deterrent===
[[File:YellowSunBomb2.JPG|thumb|right|Side view of a [[Yellow Sun (nuclear weapon)|Yellow Sun]] nuclear bomb under the wing of Vickers Valiant XD818 at the [[RAF Cosford]] museum]]

The first squadron to be equipped with the Valiant was [[No. 138 Squadron RAF|138 Squadron]], which formed at [[RAF Gaydon]] on 1 January 1955, with 232 Operational Conversion Unit forming at Gaydon on 21 February 1955 to convert crews to the new bomber.<ref name = "darling 40"/> Since the Valiant was part of an entirely new class of bombers for the RAF, the crews for the new type were selected from experienced aircrew, with first pilots requiring 1,750 flying hours as an aircraft captain, with at least one tour flying the Canberra, with second pilots needing 700 hours in command and the remaining three crewmembers had to be recommended for posting to the Valiant by their commanding officers.<ref name="Jones p79-2">Jones 2007, pp. 79–82.</ref> Valiants were originally assigned to the strategic nuclear bombing role, as were the Vulcan and Victor B.1s when they became operational. At its peak, the Valiant equipped ten RAF squadrons.<ref name="Osprey p92"/><ref>Wynn, pp. 564-565.</ref>

According to Gunston and Gilchrist, the Valiant had performed "extremely well" during the annual bombing competition hosted by American [[Strategic Air Command]] (SAC).<ref name = "bomber 79"/> American interest in the Valiant resulted in a visit to Vickers by USAF generals [[Hoyt Vandenberg|Vandenberg]], Johnson and [[Curtis LeMay|LeMay]]. Vickers test-pilot Brian Trubshaw believed that George Edwards was put under some pressure to build the Boeing B-47 under license. The only result from the visit was Le May's insistence that the Valiant pilot side-by-side seating be incorporated in the B-52 instead of the tandem arrangement in the B-47 and prototype B-52.<ref>Brian Trubshaw Test Pilot, Brian Trubshaw and Sally Edmondson, Sutton Publishing Limited 1999, {{ISBN|0 7509 1838 1}}, p.35</ref>

[[File:Buffalo R3 002.jpg|thumb|On 11 October 1956, Valiant B.1 WZ366 of [[No. 49 Squadron RAF|No. 49 Squadron]] became the first British aircraft to drop a live atomic bomb during the [[Operation Buffalo (1956)|Buffalo R3/Kite]] test]]

On 11 October 1956, a Valiant B.1 (WZ366) of [[No. 49 Squadron RAF|No. 49 Squadron]] piloted by [[Edwin Flavell (Royal Air Force officer)|Edwin Flavell]] was the first British aircraft to drop an  atomic bomb when it performed a test drop of a down-rated [[Blue Danube bomb|Blue Danube]] weapon on [[Maralinga]], [[South Australia]].<ref name="Mason Bomber p378">Mason 1994, p. 378.</ref> This occurred as part of the [[Operation Buffalo (1956)|Operation Buffalo]] [[British nuclear tests at Maralinga|nuclear tests in that area]]. Windscreen blinds were fitted in advance of the test to protect the crew from the intense flash of light from the nuclear detonation. Following the landing of the aircraft after deploying the weapon, WZ366 was assessed for potential damage and for [[radioactive contamination]].<ref>Blackman and Wright 2015, pp. 33–36.</ref>

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]].<ref name="RAF">{{cite web |url=http://www.rafmuseum.org.uk/documents/collections/1994-1352-A-Valiant-XD818.pdf|title=Individual History Vickers Valiant B (K) Mk.I XD818/7894M Museum Accession Number 1994/1352/A |publisher=Royal Air Force Museum |access-date=20 November 2015}}</ref> 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.<ref>Hubbard and Simmons 2008, pp. 61, 68.</ref> However, the measured yield was less than a third of the maximum expected although achieving a thermonuclear explosion.

On 8 November 1957 a British hydrogen bomb detonated with its planned yield in the Grapple X test.<ref name = "hub and sim 157">Hubbard and Simmons 2008, p. 157.</ref> The Grapple series of tests continued into 1958, and in April 1958 the Grapple Y bomb exploded with ten times the yield of the original "Short Granite".<ref name = "hub and sim 167">Hubbard and Simmons 2008, p. 167.</ref> Testing was finally terminated in November 1958, when the British government decided it would perform no more air-delivered nuclear tests.<ref name = "bomber 79"/>

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. They were repainted in grey/green camouflage with normal markings, replacing their [[anti-flash white]] scheme.<ref name = "flint 133"/> By 1963, four Valiant squadrons (49, 148, 207 and 214) had been assigned to [[Supreme Headquarters Allied Powers Europe|SACEUR]] in the low-level tactical bombing role.<ref name = "bomber 79"/> By this point, there had been a noticeable decline in flying rates for the type.<ref name = "bomber 79"/>