In World War II, the life of a doomed British airman (David Niven) is saved by mistake, and he falls in love with an American radio operator before the mistake is realized. Part 1 of 3. 1946.
Original movie from Internet Archive
Movie info from IMDB
Article @ Turner Classic Movies
The BFI 100
Time Out‘s 100 Best British Films: #6
Total Film‘s 50 Greatest British Films Ever