Sir Carol Reed disowned this movie, calling it "a gloomy little piece". He expected it to be a box-office disaster and was highly surprised when wartime audiences warmed enthusiastically to it.
After location shooting in Workington, a replica of the pit head was built at Twickenham Studios and later reassembled at Shepperton Studios. At forty thousand square yards, it was the largest exterior set yet built for a British movie.
Sir Michael Redgrave was normally very disdainful of movies, preferring the stage. However, as a committed Socialist, he was particularly proud of his involvement in this movie.
Sir Michael Redgrave and Margaret Lockwood, along with Cecil Parker and Linden Travers (again as a mismatched couple), starred in Sir Alfred Hitchcock's The Lady Vanishes (1938)
The earliest documented U.S. telecast of this movie took place in Philadelphia Sunday, January 2, 1949 on WCAU (Channel 10).