Bob Hoskins' voice was dubbed over by another actor from Wolverhampton out of fear that Americans wouldn't understand his London accent. After Hoskins threatened to sue Jack Gill and British Lion, the dubbing was removed. He was supported by Richard Burton, Sir Alec Guinness, and Warren Beatty.
This film is Pierce Brosnan's feature film debut, his part was supposed to be completely silent, but he improvised one word of dialogue, "Hi".
Harold's plans for the London docks prophetically predicted the creation of Canary Wharf.
In her 2008 autobiography, "In the Frame: My Life in Words and Pictures", Dame Helen Mirren claims that it was at her insistence that her character "Victoria" was made into a more complex character than just the stereotypical mob moll.