Source: Giants of the Sky. Bill Gunston. PSL. Pg 212
In 1942, with USAAC handling the day bombing campaign against Germany, the Bristol Buckingham became redundant.
(the Mosquito also contributed [
Bristol 163 Buckingham - bomber])
This left a hole in the Bristol design office and, at the Ministry, they asked if Bristol would like a design study contract for a bomber to carry 80,000 lb to Berlin. (a B-36-class bomber). No type number was raed. This was at first a free exercice but later, 8xBristol radials buried in the wings made the wing very deep, and upper and lower four cannon turrets made the fuselage portly. The butterfly tail, November 1942 design was 225 ft span and 5,000 sq ft area. Rotol contra-rotating 6-blade propeller was 16 ft in diameter. The aircraft would have been unpressurized and defensive armament would have comprised 12x 20 mm cannon.
In 1946, a Bristol advertisement (I think hesham found it and it's here in the forum) appeared showing a direct civil version of the "100 ton bomber". Finally, although a different configuration was selected for Type Number 167 Brabazon, it retained technical solutions developed in the bomber design work.