Barnes Wallis, the inventor of the bouncing bomb, knew from the start of the Second World War that he would have an important role to play.
His daughter, Mary Stopes Roe, reveals her memories of the start of the war and how she and her siblings understood that her father was under pressure both professionally, and in terms of looking after his young family.
"We all just knew that he was very pressured," says Mary Stopes Roe. "I think we knew from 1939 actually. We were camping in Dorset then and I remember on 1 September we were having a cream tea in the square in front of Wimborne Minster and the loud speaker went round saying that blackout was being enforced in London and that children were being evacuated from London and I remember my father jumping up immediately and saying that he must go at once."
However, it wasn't until the beginning of 1942 that Wallis came up with the idea of the bouncing bomb.
"I thought of what would be an engineer's way of stopping the war," he said, "and that would be to cut off the power supply to their great armament factories in the Ruhr. Which involved bombing and destroying the dams, because it takes 100 to 150 tons of water to make one ton of steel and if we rob them of all their water supply, they couldn't produce steel and the ear would come to an end."
This blog is dedicated to the memory of Flying Officer Harvey Glinz, an air gunner with 617 Squadron on the Dambuster raid, who was killed in action, aged 22.