There was no follow-up raid because aerial photography showed that the new anti-air raid defences on the dam installed after the attack would have made a second raid suicidal.
Upon hearing of the immense 40% fatality rate sustained - with 53 men killed, along with 3 captured - Barnes Wallis is said to have burst into tears. Despite his expertise as one of Britain's leading wartime engineers, he was a pacifist at heart. In 1969, Wallis spoke of how "the most regrettable matter of the whole project was the fact that a large number of women and children drowned" in the 336 million tonnes of water that broke from the dams. It demonstrated how heavily the Dams raid weighed on his mind.
The operation did not bring about the long-term crisis for which planners in the Air Ministry and Ministry of Economic Warfare had hoped. There were two main reasons for this: the attack had focused on the wrong combination of dams, and it was planned as a stand-alone operation by a small force rather than as part of a sustained campaign by a larger one. To bring about a systemic economic failure the RAF needed simultaneously to destroy a number of dams - and in particular the Sorpe as well as the Möhne - and the pumping systems that linked them, and then re-attack them at intervals to prevent repair.
The squadron's mascot, "Nigger", was given beers to drink as depicted in the movie. However, the dog had a habit of urinating on people's legs which made the dog unpopular with many of the squadron's personnel. Also, the dog was killed when hit by a car, but unlike in the movie, the driver did attempt to avoid the dog and the occupants of the car were injured as a result. Any reports of Nigger's grave being opened, and the bones revealed proving not to be of a dog, are false. The grave was never opened, and is protected to this day.
According to Richard Todd's autobiography, the scene that upset him most during filming was the finale where his character Guy Gibson goes off to write letters to the families of the men killed on the raid. Todd, a paratrooper combat veteran of World War II, had written such letters for real. The scene brought it all back for him.