This, believe it or not was supposed to be built as a testbed for a fighter-interceptor and was proposed pretty much just after the Defiant specification came out. It was a three-seater armed with a 360 degree in azimuth four 20 mm cannon turret mounted on top, the turret actually got legs in the R &D department of the Air Ministry as there were several proposals for it, including mounting two of them on a Manchester and on the B.1/39 specification, which the British termed "The Ideal Bomber", which was never built...
Hi! https://www.warbirdsforum.com/topic/366-additional-raf-might-have-beens/ "The B1.39 spec was to carry 9,000lb over 2,500miles cruising at least 280mph. Maximum bomb load was to be 10,000lb and some could be carried externally if necessary. Provision was made to stow 20 x 250lb or 500lb...