This film has a very open ending - just as in the true case upon which the film is based you don't know whether or not Madeleine killed her lover, as the jury renders a uniquely Scottish verdict of "not proved" which splits the difference between outright acquittal and conviction. Such a film would have been difficult to make in America at the time, as the U.S. production code of the period so demanded clear villains and heroes and swift and sure punishment of the villains.
There's a great use of lighting and shadow in this film, effectively differentiating the dark back-alley scenes where Madeleine meets her poor lover on the sly from those well-lighted ballroom and daytime scenes where she is courted by her family-approved suitor, William Minnoch. Ann Todd gives a very guarded performance here as Madeleine, and maybe that was necessary to add mystery to what and how she was thinking about her predicament.
I was particularly impressed by Ivan Desny as Madeleine's backstreet lover, Emile L'Anglier. He reminded me a great deal of Orson Welles in his physical features and even some in his acting style. Desny's performance is also subtle, but not so subtle that you can't see that his character is more in love with the idea of becoming a moneyed gentleman again than he ever could be with Madeleine herself.
This is one of David Lean's early films, and there is one scene in particular that reminded me of his last - "A Passage to India". That scene is when Madeleine is being conducted to court in a carriage accompanied by a police officer with the mob getting out of control outside. It's not just the alleged crime that has the mob stirred up, its Madeleine's rank and privilege as well. There is a similar scene in "Passage to India" as Judy Davis is conducted to court to testify. In that film it's her accusations of an Indian of the crime of attempted rape combined with her status as a member of the British aristocracy that has the crowds riled up. I wonder if Lean borrowed on the ideas from this film when making his last.
At any rate it's worth a look, just don't expect things to be wrapped up neatly as they almost always were in courtroom dramas in American films of the time.