Continuity mistake: Lawton and his designated victim are looking at the cops fishing out of the corpse. From the aerial view we see Horton and Wright passing by in a gondola. Between two shots Richard Griffiths says "Absolutely...beautiful." There's a jump in continuity: Patsy Kensit's arm position changes, and the corpse that was just being pulled aboard now lies on the deck. (00:30:35)
Factual error: The titular character, "the bellboy" works at a hotel in Venice and has an italian accent, but whenever he actually speaks in Italian it is obvious that he is no native speaker, he really butchers his lines in the language.
Continuity mistake: Horton is upstairs at the villa with Miss Wright. She sits on the bed, and the documents bag is facing up with the metallic buckle showing. In the frontal views of the bed though, the bag is upside down. (00:22:00)
Continuity mistake: Mr. Maurice Horton is dining on the terrace while the bellboy "envelops him", as he puts it. In the close-up of the content, Richard Griffiths 's fingers hold the card by the top left corner. In the previous and following shots though, his hands are at the middle of the card and, even more importantly, there's a flyer behind it that is missing in the close-up. (00:09:25)
