Complex sentence: It was written by Eric Ambler and Peter Ustinov and directed by Carol Reed, and was based on their 1943 film "The New Lot", which was made as a training film for the Army Kinematograph Service.
Split into simpler sentences: It was written by Eric Ambler and Peter Ustinov and directed by Carol Reed. The three had originally produced the 1943 film "The New Lot", which was made as a training film for the Army Kinematograph Service.