Celia Johnson turns in a tour de force performance in this all-time classic dealing with the exquisite pain and misery of an impossible love. Trevor Howard is excellent as always, but Ms. Johnson's mastery of nuance is simply superb.
Interesting trivia: Rachmaninoff's Piana Concerto #2, excerpts of which played throughout the movie, was Princess Diana's favorite.
By the way, it is free on youtube.