One day, Noël Coward visited the set and after seeing how the crew staged and wrapped up an elaborate sequence in about two hours, decided to use most of them on Eroi del mare (1942).
The film has no musical score at all (a rarity). The opening titles play over the sound of the bomber's engines. Michael Powell had decided on complete naturalism for the film's soundtrack. "There would be no music. There would only be the natural sounds of a country at war. It was not a documentary; it was a detached narrative, told from the inside, of what it is like to be a pawn in the game of total war."
The extra squadron members were all active members of the Royal Air Force (XVI) squadron.
Sir George Corbett (Godfrey Tearle) was reported to be fashioned after the real-life Sir Arnold Talbot Wilson. In 1939, he joined the Royal Air Force at age 55. He died in 1940 when his airplane crashed in France.
Second credited theatrical movie of Sir Peter Ustinov, the first being Let the People Sing (1942), which was released in August. This movie was released in October.