Dramatization of an actual operation in World War II in which low level Bombers from England drop skimming bombs into reservoirs in the Ruhr water system to cause floods destroying much of Germany's industrial base. Written by John Vogel <>

Errors and ExplanationsEdit

Internet Movie DatabaseEdit

Audio/visual unsynchronisedEdit

  • After the first failure of the full size test bomb, Guy Gibson, Bob Hay and Barnes Wallis are saying goodbye to each other. Bob Hay's mouth moves but what he says to Barnes Wallis is not heard. (at 46:25) Perhaps he was whispering?

Movie MistakesEdit


  1. The system devised to get the height right was, in the film, said to have been thought of by the 617 Sqn crews following a visit to the theater. In reality it was devised by the 'boffins' at Farnborough. It may be possible that the boffins were inspired in the manner shown in the film!
  2. The spotlight method of altitude finding depended on the plane being level. But during the first practice flight at 60 feet, we hear the crew member's altitude instructions go right on without a break while we are also seeing the plane bank steeply for a sharp turn. This really happened. The Lancaster involved - M for Mother - nearly ditched in Eyebrook Reservoir in Lincolnshire as a result.
  3. Evidently the Upkeep's design was still secret. In all the shots of the Wellington test drops some one has taken the trouble to go over the bomb with some kind of marker pen making it appear as a large black blob. You never see footage of the real Lancaster test drops. The Mosquito seen later is not dropping the upkeep but a smaller anti shipping version that didn't work, and hence was shown uncensored. A Mosquito couldn't possibly have lifted a full size upkeep mine. This is hardly a fair criticism of a film made in 1954, and it doesn't really constitute a film mistake. They had to put a story based on a genuine historical event on the screen when the facts about that event were still protected by the Official Secrets Act, and by and large they did a good job. The Dam Busters is acknowledged as a partially fictional version of the famous raid, made in a time when special effects were primitive (on modern standards), and in their version of events the test drops of the Upkeep bombs were made by Mosquitoes, only two dams were attacked (five, in reality) and Guy Gibson thought up that method of setting the altitude of the bombers by watching the spotlights at a strip show. All fiction, of course, but in this film's reality, it is fact - and that's all part of the charm of this classic film.
  4. A train is shown being wrecked by the floods, dramatically crashing off the right hand track as it approaches us. German trains run on the left hand track. You don't see the track. Water is already flooding the railway and the train is derailed when it hits it. It looks like a single line anyway, but the swirling water makes it impossible to tell.
  5. One of the shots of individual British Lancaster bombers approaching one of the dams is actually and incorrectly an American B17, seen for only a second or two. (Unnamed Movie Mistakes Member) I have just watched the film, paying meticulous attention to the aircraft used. They appear to have used three - perhaps four - real Lancasters and any number of models. At no time in the film is a B17 visible.
  6. The Bouncing Bomb was still on the secrets list when the film was made in the fifties.[N 1] The makers of the film made the mock up bomb too big. It would have intruded right into the Lancaster's fuselage, through the main spar, and the wings would have fallen off. The filmmakers were granted unprecedented access to footage of the real Dam Busters in action, including test flights and dropping of the 'Upkeep' bomb. The Lancasters you see flying were the real thing - and the 'mock up bombs' fit perfectly underneath and forward of the main spar, just like the real, smaller bombs did.[3]


  1. In fact, Wallis wasn't allowed to submit a patent until late 1963![2]


  1. Daily Telegraph website
  2. I'll Drink to That!
  3. Movie Mistakes
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