Because it was started and completed so soon after the declaration of war and was seen to show how useful films could be in wartime, this film is considered to have done a lot towards allowing the British film industry to remain active throughout WWII, unlike in WWI when all cinemas were closed and filming effectively stopped for the duration.
Looking back at this movie, Michael Powell described it as "an outrageous piece of propaganda, full of half-truths and half-lies, with some stagy episodes which were rather embarrassing and with actual facts which were highly distorted..."
At approximately 55 minutes into the film, segments of the film "Fire Over England" appear, together with a voice-over by the narrator reading passages from Lord Macaulay's poem "The Armada." This is a flashback to 1588 when Philip II sent his Spanish fleet against England in the reign of Elizabeth I.
The twin-engine bombers taking off on the mission to bomb the German pocket battleships at Kiel are a mix of Vickers Wellingtons, Type 290 Mark I's and Type 408 Mark 1A's. Note the advanced, unusual, yet very strong and lightweight geodesic construction of the fuselage visible during the interior shots and through the perspex windows from the exterior. Produced from 1936 to 1945, over 11,400 Wellingtons of all types were made.