The Westland Scout / Wasp family of light helicopters are among the most instantly recognizable in the UK arsenal. Despite their archaic appearance, notably on account of the exposed turboshaft engine, they were used extensively for the better part of three decades fulfilling many of the same roles as other designs such as the US OH-6 and OH-58 for light multi-purpose operations such as observation, search and rescue (SAR), casevac, and light attack missions (even equipped with anti-tank missiles) as the Scout. It was also developed successfully for naval operations as the Wasp, particularly as an anti-submarine warfare platform capable of being equipped with torpedoes or depth charges and they were found extensively on Tribal and Leander-class frigates during the Cold War. Foreign operators included Australia, Brazil, Indonesia, Jordan, Malaysia, the Netherlands, New Zealand, and South Africa, and were retired from UK service in the early 1990s after being replaced by the Lynx.

The Saunders-Roe P.531 prototype was first flown on 20 July 1958 and was the basis of the Scout after the company's acquisition by Westland. Both military and naval versions were developed in parallel, the first to enter service being the land-based Scout AH.1 with a skid landing gear. Extensive trials eventually led to the navalized Wasp HAS.1 which differed by having a more powerful engine, foldable main rotor blades and tail rotor pylon, and a quadricycle landing gear.