Wallis had worked on the Vickers Wellesley and Vickers Wellington bombers and while working on the Vickers Windsor, he had also begun work, with Admiralty support, on an anti-shipping bomb, although dam destruction was soon considered.

The mission grew out of a concept for a bomb designed by Barnes Wallis, assistant chief designer at Vickers. Despite rapid repairs by the Germans, production did not return to normal until September. An estimated 1,600 civilians – about 600 Germans and 1,000 enslaved labourers, mainly Soviet – were killed by the flooding. Factories and mines were also damaged and destroyed. Two hydroelectric power stations were destroyed and several more damaged. The Möhne and Edersee dams were breached, causing catastrophic flooding of the Ruhr valley and of villages in the Eder valley the Sorpe Dam sustained only minor damage. Operation Chastise, commonly known as the Dambusters Raid, was an attack on German dams carried out on the night of 16/ by 617 Squadron RAF Bomber Command, later called the Dam Busters, using special ' bouncing bombs' developed by Barnes Wallis. 1,000 prisoners and slave labourers, mainly Soviet) Eder, Möhne and Sorpe (Röhr) rivers, Germany

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