The B1/39 specification was intended to produced the "ideal bomber" for RAF world wide operations, the projects selected for further development were those by Bristol (Model 19) and Handley Page (HP60). Due to the onset of WW2 and notably the establishment of the Ministry of Aircraft Production under the control of Lord Beaverbrook, these designs,(along with many more) were suspended then cancelled around May-June 1940.
When new heavy bomber designs were again requested the B1/39 types no longer met projected operational requirements. One of the problems being that the designs were based on the use of smaller bombs (2,000 lbs maximum) and heavy defensive weapons (ie turrets with 4 x 20mm cannon), the new requirements stressed the use of much larger bombs (and many more of them) therefore much larger aircraft.
Lord Beaverbrook did what was required for Britains defence in 1940 but some beautiful and/or interesting aircraft projects fell under his axe. :-[