A wedding scene was added in order to appease U.S. censors.
The evil traders were invented for this film and are not part of the novel.
The movie is a very loose adaptation of the book which was published in 1908. It contains a few scenes from the book, tones down the nudity and sexual content so much that they're almost non-existent and re-writes the dialog completely.
The playwright John Osborne, then a teenager, was considered for the role of Michael.