It was made in 1937, shelved, and wouldn't have been released if not for 'Gone with the Wind', and the fact that they were now both hot properties. It doesn't flatter either of them. It's really for die-hard fans, and lovers of tragic romances who can overlook some minor morality issues.
A film that challenges the use of circumstantial evidence in the courtroom. Most of the criticism has been leveled at the sets, direction and acting. I think the film works on a different level. The entire time we know who the murderer is and that the man that stands accused is innocent. So the long drawn out courtroom scenes aren't to drive the plot, but to drive home that point that justice is fallible.
Some of the mechanizations within the story are a bit forced. Considering the cast involved (Laurence Olivier and Vivien Leigh), the acting is rather stagey and subpar. The conflict within Olivier should have been stronger (almost immediately, he wants to do the right thing... the film would have been stronger had he actually contemplated letting the wrongly accused man hang). Overall a disappointing film.