Editing Vickers Valiant (section)

===Production===
[[File:Vickers Valian B.1 WZ393 90 Sqn SGT 10.06.57.jpg|thumb|Valiant B(PR)K.1 WZ393 of 90 Squadron in original all-metal finish displaying at Blackpool Squires Gate airport in 1957]]
In April 1951, an initial production order for 25 Valiant B.1 (Bomber Mark 1) aircraft was placed by the Ministry of Supply on behalf of the RAF.<ref name="Aero Aug80 p400">Burnet and Morgan ''Aeroplane Monthly'' August 1980, p. 400.</ref> The timing of this order was key to establishing production quickly. Due to shortages of [[steel]] and other materials while setting up an assembly line at Brooklands, substantial portions of the production [[Jig (tool)|jigs]] for the Valiant were made from [[concrete]].<ref name = "bomber 77">Gunston and Gilchrist 1993, p. 77.</ref> The first five Valiants produced were completed to a pre-production standard, the first being WP199. On 21 December 1953, the production aircraft conducted its first flight; this had again occurred within the schedule that Edwards had promised.<ref name="Jones p37">Jones 2007, p. 37.</ref><ref name = "bomber 77"/>

On 8 February 1955, this first production Valiant was delivered to the RAF.<ref name="Osprey p12">Brookes 2012, p. 12.</ref><ref name = "flint 131">Flintham 2008, p. 131.</ref> Britain's "V-bomber" force, as it had been nicknamed in October 1952, formally entered operational service on that day. The Victor and Vulcan would soon follow the Valiant into service, for a total of three types of nuclear-armed strategic bombers in RAF service. In September 1957, the final Valiant was delivered.<ref name = "hub and sim 26"/> All production aircraft had been delivered on time and below budget.<ref name = "bomber 78"/>

A total of 108 Valiants were manufactured, including the sole B.2 prototype. In addition to its principal role as part of Britain's [[nuclear deterrent]], the Valiant bomber also dropped high explosive bombs. The bombers were followed into service by a strategic reconnaissance version and a multi-purpose version capable conventional bombing, [[aerial reconnaissance]] and [[aerial refueling|aerial refuelling]]. 18 squadron operated 6 Valiants with [[electronic countermeasure]]s equipment.<ref name = "black wright 19 20">Blackman and Wright 2015, pp. 19–20.</ref> Valiants of 90 and 214 squadrons were used for air refuelling through the addition of a Hose Drum Unit (HDU) in the bomb bay, mounted on the same suspension units that were also used for bombs.  This meant that for refuelling, the bomb-bay doors had to be opened so that the refuelling hose could be streamed (unlike later tankers where the HDU was flush with the under fuselage rather than inside a bomb bay). Several Valiants were also used for testing and development purposes, such as its use as a flying testbed during trials of the [[Blue Steel (missile)|Blue Steel]] nuclear-armed [[standoff missile]], which was later added to the arsenal of munitions the other V-bombers were equipped with.<ref name = "black wright 24 26">Blackman and Wright 2015, pp. 24–26.</ref><ref name = "flint 133">Flintham 2008, p. 133.</ref>

Unlike the Vulcan and Victor, the Valiant did not see the production of a more capable mark 2 model.<ref name = "flint 131"/> 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. In 1964 [[Fatigue (material)|fatigue]] was discovered due to the increased air turbulence in low level flying and led to the type's premature retirement. 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... The Air Ministry was not interested..."<ref name = "flint 133"/> The Valiant was Vickers' last purpose-built military aircraft. It was followed by the [[Vickers Vanguard|Vanguard]], a passenger turboprop designed in 1959, and the [[Vickers VC10]], a jet passenger aircraft in 1962, also used as a military transport and tanker by the RAF.<ref name = "flint 131"/>