During the 1950s, US paranoia regarding the perceived Soviet threat reached fever pitch. To combat the Soviet Union's overwhelming numerical superiority, the US military elected to utilise not only it's own considerable production capacity to the fullest but also that of it's allies. One of the initiatives that stemmed from this was the 'Double Century' series of tactical fighters which used the '200' designator series to free the 100s for indigenous designs.
The Supermarine Swift FR.5 had impressed many during various NATO photo-recce exercises. This interest was heightened further when Supermarine announced the FR.9 variant. It's slim-line, area-ruled fuselage and uprated Rolls-Royce Avon promised supersonic performance at low level. The US made an initial order for 205 as the Supermarine RF-201A Swift. Since the RAF was far more enamoured with the P.1083 Hunter, this offered no problems in Supermarine's production scheduling.
It was planned that the RF-201s would supplement and eventually replace the RF-84F Thunderflash in both US and NATO service, in turn freeing up more expensive F-101 Voodoo airframes for the important tactical bomber role. Used by several NATO air arms as well as the USAFE and ANG, with production eventually totalling 335 aircraft, the Swift gave sterling service for many years.
While nominally obsolete by retirement from US service in 1969, the Swifts had been retained to provide a most useful recce capability in the European Theatre as the Vietnam War drew in ever larger numbers of reconnaissance assets.
Supermarine RF-201A Swift 184th TRS by
mtpalmer1, on Flickr