Continuity mistake: Watch Gwenda's headrest after she leaves the station in her car. It disappears between shots.
Continuity mistake: When Mr Stimpson drives into the police car you can see damage to both cars; when the police car drives off the back end of it looks unblemished.
Audio problem: After Stimpson misses the train he gets a taxi home. The taxi is a Ford Granada mark 1 with the sound effect for a diesel engine. This range of cars was only available with petrol engines.
Factual error: On the drive to Norwich, Stimpson wants Laura to take a turn for Northampton. But Northampton isn't on the way to Norwich. Northampton is pretty much north of London, and Norwich is East. Northampton could only be on the way to Norwich if one started way to the West of Northampton, in which case one would not have been able to get a direct train to Norwich in the first place, as Stimpson intended.
Factual error: There are profound problems with the geography of the U.K. In the beginning, Stimpson is at a train station. He wants the Norwich train, but instead gets on a train bound for Plymouth. There is no station where you could get a train to both. Plymouth is in the South West. To get there from London, you go out of Paddington. Norwich is in East Anglia and you get there from Liverpool Street.
Revealing mistake: During Stimpson's speech toward the end of the film, you can see that it's John Cleese himself giving his sleeve a good pull under the table, when his taped-on sleeve accidentally comes off.
