When Nosey offers Bisson a bowl of stew, Michael Gough's voice on the soundtrack says "Buzz off!" but his lips form the words "Drop dead!" Presumably the line was changed when Mike Morgan died suddenly before the movie was released.
Joyce Cary, the author of the novel which inspired this movie, based the role of the self-destructive painter on his good friend, the great Welsh poet Dylan Thomas.
Sir Alec Guinness felt that an educated accent for Gulley Jimson would be suited to an artist, but was not right for an eccentric. "So I tried to find a voice in which no one would be able to detect an accent of any sort, a kind of gritty, rough manner of speaking. When I found it, I felt myself free to just relax on that and say the lines as they came."
One day Ronald Neame found Sir Alec Guinness sulking in his dressing room, refusing to come to the set. According to Neame, Guinness felt he hadn't been stroked enough and explained, "Actors are emotionally 14-year-olds. We need to be chastised like children, and we need to be hugged and told we're doing fine work. We are the children who never grow up."
Mike Morgan (who played Nosey) fell ill with meningitis shortly before filming ended and died 10 days before the end of shooting before its completion. As a result, an unknown actor dubbed many of Morgan's lines in post-production.