It was the Blackburn B20
The aircraft was built at Blackburn's new Clydeside factory at Dumbarton. It took three years to complete first flew about March 1940, crashed into the River Clyde off Gourock Head 7th April 1940.Two crew escaped by parachute but the Pilot Flt Lt Bailey was killed. B-44 a retractable float fighter was to have followed but advances in other fields made the idea obsolete.