The Fibber was an attempt to create an aircraft which could deliver a payload of bombs and hold off enemy fighters without the need for an escort. Early versions were successful, but mainly due to their speed. Eventually the Fibber proved to be a highly adaptable aircraft, with Bomber, pure fighter, Interceptor and Reconnaissance variants, as well as being developed into a jet fighter.

The Mk.1 was the most basic of the Fibber line, designed to carry bombs and engage enemy fighters. These aircraft could outrun the early 'Saviour' aircraft of the WIADF, and provided vital relief to the crews of 'Conveyor' bomber crews who had been taking heavy losses.