Richard Addinsell composed the Warsaw Concerto for a British made film- "Suicide Squadron" as it was known in USA release. The British film title was 'Dangerous Moonlight'. The film came out in 1941. The music became more popular than the film. And more popular than some of Addinsell's other film scores like 'Gaslight' in 1939, 'Blythe Spirit' in 1945 and 'A Christmas Carol' in 1951. The film's love-story plot revolves around the fictional composer of the piece, a piano virtuoso and "shell-shocked" combat pilot, who is a refugee in England from the World War II occupation of Poland and considers returning to Poland to rejoin the war. The actor, Anton Walbrook, was an accomplished amateur pianist, so his hands are seen playing in the film, but in fact the music on the soundtrack is played by an uncredited pianist, Louis Kentner. [Visit Wikipedia for more info...]
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Richard Stewart Addinsell (13 January 1904 – 14 November 1977)
The film, "Dangerous Moonlight", VHS video is available: