Dean Stockwell was cast at producer Jerry Wald's insistence to help the film's chances of distribution in the United States.
Jack Cardiff chose to film in black and white as he felt that Technicolor was too pretty for such a gritty subject.
At 20 minutes and 14 seconds, Trevor Howard's performance in this movie is one of the shortest ever to be nominated for an Academy Award for Best Actor in a Leading Role.
Wendy Hiller was always Jack Cardiff's first choice to play the mother. He had been told that this was impossible as she was performing in a play on Broadway. Luckily for Cardiff, the play folded very quickly and Hiller was delighted to take the part.