Long before the outbreak of WWII, British Strategic Planners were looking at ways to cripple German industry in the event of war.Their main interest lay in the industrial heart of Germany...the Ruhr Valley.As early as 1938 the problems of attacking the dams which provided Hydro-Electric power to the Ruhr region were discussed. Aircraft, bombs and bombsights in use were not capable of pinpoint accuracy. Dams made very small targets from above, while attacking over the water at low level was fraught with danger. At the same time as these discussions were taking place, Dr Barnes Wallis, assistant chief designer at Vickers Armstrong, was exploring the same problem.He reasoned that if the dams could be breached by a few bombs, it would save thousands of tons bombs that would need to be dropped on the factories themselves.Wallis initially envisaged a 10 ton 'earthquake' bomb, which after release would reach supersonic speed.It would bury itself deep in the ground before exploding, the resulting shockwave would literally shake the target from it's foundations.The one small problem with this scheme was, no aircraft in existance could carry such a load....undettered, Wallis simply designed one.There was no official interest in this aircraft, designed for a single purpose and Wallis looked for another solution to the dams problem. Throughout 1940 and into 1941 Wallis conducted tests on model dams.These tests proved that if a bomb was dropped any distance from the dam, the blast was quickly dissipated by the water.However if the bomb were in contact with the dam wall, the water would concentrate the blast.This also meant a smaller bomb would be required, perhaps small enough to be carried by the Avro Lancaster which had recently entered service. Knowing the dams would be protected by anti-submarine nets, Wallis looked at ricochet as means of delivery.In April 1942 Wallis took over the National Physics Laboratory at Teddington, for three months he fired machined spheres up and down the huge ship testing tank. Late in 1942 Wallis got permission to convert a Wellington III, BJ895, so that it could carry 2 inert spherical mines, which it duly dropped off Chesil Beach on the South coast, in a series of tests during December 42 into January 43. After the success of the trials official support grew for the project.On February 26th 1943, at a meeting in the Ministry of Aircraft Production, it was announced that every endeavour should be made to produce the bomb and the aircraft to deliver it at the earliest possible date.This was to take priority over all other Vickers projects and Avro would convert 3 Lancaster B1's as soon as possible for trials of the full size weapon, now code-named 'UPKEEP'... The final design for Upkeep was cylindrical, with 4 fuses ( 3 Hydrostatic, which would be detonated by water pressure, and a self destruct fuse that once armed, would destroy the bomb 60 seconds after release.) fitted at one end. Almost 50 inches in diameter and 60 inches wide, the Upkeep mine (this was not a bomb) weighed 9250 Lbs. With Wallis now committed to producing the weapon, attention shifted to the RAF, a Squadron, a man to lead it and the crews to man it.......