Blackburn B-54 (YA7) was a prototype shipborne anti-submarine airvraft designed to meet Spec. GR17/45. The monoplane design featured a tricycle undercarriage and an inverted gull-wing, fitted with an effective high-lift flap system drawing upon experience with the B-48 Firecrest. The YA7 was flown for the first time from Brough on 20th September 1949 before carrying out deck landing trials on HMS Illustrious, starting from 8th February 1950. The B-54 was modified and redisgnated B-88 which flew in July. Following competitive trials, the Fairey Gannet was eventually selected in March 1951 and it was this type that entered large-scale production.