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.
This is one of the films that George Lucas used clips from to edit the rough cut of Star Wars: Episode IV - A New Hope (1977) (which utilizes many features of the finale of this film quite closely, notably the briefing, the ground staff waiting for news, the troika formation of the attacking aircraft and so on). In Addition, the following exchange from this film is reproduced almost verbatim (with the exception of the characters' names) in "Star Wars": Gibson: "How many guns d'you think there are, Trevor?" Trevor: "I'd say there's about 10 guns - some in the field and some in the tower".
Footage used to show the bombs as they skipped on the surface of the water towards the dams was drawn from footage of the bombs being tested. Backspinning the bombs gave them gyroscopic stability when skipping across the water, then held them against the dams as they sank. To conceal the backspin, which was still a state secret at the time of filming, the bombs in the footage were painted over frame by frame.
Richard Todd, who plays Guy Gibson VC in the Dam Busters, also played Major John Howard in "The Longest Day". Major Howard led the first action on D Day, the attack and seizure of the bridges over the Orne River and Caen Canal,now known as Pegasus Bridge In reality, Richard Todd, who was a paratroop Captain on D Day, led the first of the main force paratroops sent to relieve the Pegasus Bridge attackers.
According to Richard Todd's autobiography the scene that upset him most during filming was the finale where Guy Gibson goes off to write letters to the families of the men killed on the raid. Todd, a paratrooper combat veteran of WW2 had written such letters for real. The scene brought it all back for him.
Wing Cmdr. Gibson mentioned the "Tirpitz" as a possible target. This German battleship was later sunk, by 617 Squadron, using 6-ton "earth quake" bombs called Tallboys which were also designed by Dr. Barnes Wallis.
Richard Todd was an established star at the time with the right to refuse the studio's choice of directors. It was only after dinner with Michael Anderson (and their respective spouses) that the two men realized they got on quite well, and Todd approved Anderson as director.
Memory of the war was still quite fresh in British minds when the movie was released in 1954. The excitement and interest generated were such that, exceptionally, the Royal Command Performance of the movie had to be repeated the following night. Frank Phillips was present and read the official announcement of the raid, as he had done on radio in 1943 and in the film.
To avoid unwanted reflections, in numerous scenes, the actors have the lenses removed from their goggles and replaced with blank card. In the "this is bloody dangerous!" scene, it is very noticeable on the bomb aimer's goggles.
When the Lancasters first arrive at Scampton there is a transport aircraft in the background. It is a Handley Page Hastings, which was a postwar type, and it is painted in a 1950s scheme with postwar roundels on the wings.