A question: Does anyone know of anyone viewing Witness for the Prosecution for the first time (and knowing nothing about the film in advance) who was able to acccurately predict the surprises at the end? I would suspect that very few ever did. For first time viewers, I suspect that the ending is the final capper of a great suspense ride. Unfortunately, I'll never be able to relieve the thrill of that surprise ending again.
But that's one the great things about this masterful courtroom thriller. The film is so wonderfully directed and richly acted by a great ensemble cast, with some marvelous character performers, such as you mentioned, mrroberts, and that wonderful, often witty, dialogue (particularly love the exchanges between Laughton and Lanchester) that I still get a great kick out of repeat viewings of the film EVEN THOUGH I know the ending.
You know that a film is a great one, such as Witness, when it holds up so well to repeat viewings.
I've read some reports suggesting that Marlene Dietrich was denied an Oscar nomination because the studio, obviously for reasons of elements of surprise for its audience, was successful at keeping her impressive Cockney tart characterization in the film under wraps. Therefore she didn't get as much acclaim as an actress as might have been the case otherwise.
It's sad, of course, that this was Tyrone Power's final completed film. However, the acclaim that this film received, plus, I'm sure, Power's own satisfaction at his own contribution to this Billy Wilder production, must have warmed his actor's heart. Power's both winning and sly performance adds a lot to the production.
Finally, Witness has one of my two favourite Charles Laughton performances (the other being Hunchback of Notre Dame), both films full demonstrations that this complex English actor could be, when given the right role and director, one of the truly great actors of cinema. With the exception of Hobson's Choice, it had been a long time since the actor had had such a good role.
Wilder and Laughton (along with Ty Power) became the best of friends while making this film, and actually spent some time travelling together. Wilder would later recall Witness as having the happiest set of any film that he directed. Five years later the director would tell Laughton that the role of "Moustache" was his in Irma La Douce once he recovered from his bout with cancer.
Of course, Laughton wouldn't recover, dying in December, 1962. But what an act of friendship it was for Wilder to fill this old actor's heart with the joy of knowing that a good role awaited him once he was back on his feet again.