The increasing speed and attack range of the submarine threat, and the increased range at which this threat could be detected led to a Royal Navy requirement for a "Manned Torpedo-Carrying Helicopter" (MATCH).
The first prototype Saro P.531 flew on 20 July 1958,[REF] with the prototypes being subject to detailed testing by the Royal Navy, including the evaluation of several different undercarriage layouts, before settling on the definitive arrangement.