A 12,000 lb bomb undergoes a fragmentation test.
Item title reads - War secret.
Location of events unknown.
M/S's of 12,000 lb bomb, designed by Mr C. N. Wallis of Vickers, lifted up by ropes and swung around. M/S wall of armour plated screens which will take impact of fragmentation test. M/S as the wall is examined before the trial. M/S as telephonist speaks on phone to recording office, various interior shots of the office and its recording equipment etc. M/S as man works on wires. M/S two men examining bomb. M/S's recording instrument panel. M/S's as distance between bomb and target is measured. M/S showing the plate which is nearly as thick as a man's hand.
M/S flag at full mast, C/U as button is pressed and pendulum swings. Two L/S's of the huge explosion. Camera pans across to show hole in wall. M/S and C/U as experts examine result on strip of paper. Various shots of the crater caused by the bomb, a man climbs about in it and camera pans across it. M/S part of steel plate with holes in, they lift it up. C/U pan up the plate, a man looks through the holes. Library footage shows aerial views of Lancaster bomber using these bombs to sink the German ship "Tirpitz".