Designed as a seaplane fighter, TG263, the first of three prototypes made its first flight on 16 July 1947. The project was later shelved largely due to supply and production problems with its Metropolitan Vickers Beryl engines. The aircraft was briefly reprieved for the Festival of Britain in 1951, flying as G-12-1, after which it was presented to the College of Aeronautics at Cranfield remaining with them until moved to the Skyfame museum in 1966. When Skyfame closed in 1978 the aircraft moved to Duxford and was loaned to the Solent Sky Museum in 1991 before being purchased by them in 2011.

Prototype TG263 used by Saunders-Roe for experimental research under civil "B-type" registration G-12-1