First flight of the Saunders-Roe P.531
Sunday, July 20, 1958
The aircraft (G-APNU) was piloted by Saunders-Roe Chief helicopter Test Pilot Ken Reed. The Type would eventually be developed into the Westland Wasp and Westland Scout.
The source reference below provides a very detailed technical description of the aircraft.
Source: "Saunders-Roe P.531", FLIGHT 8 August 1958, Page 199-203