 A development of the F.9/37 as a night fighter, for a new Air Ministry Specifications F.29/40 – known unofficially as the Gloster Reaper – was dropped so that Gloster could concentrate on existing work and on the nascent British jet projects.Gloster had designed a twin-engined turret-fighter for specification F.34/35 but the single-engined Boulton Paul Defiant for F.9/35 was seen to cover both requirements and the F.34/35 design dropped.Less than two years later, F.9/37 for a "twin-engined single-seat fighter with fixed armament" was issued.