Revealing mistake: During the riot scene, the canteen walls wobble. This is most noticeable when a prisoner is trying to pull the notice board off the wall.
Porridge (1973)
1 revealing mistake in Disturbing the Peace - chronological order
Starring: Fulton Mackay, Ronnie Barker, Brian Wilde, Richard Beckinsale
Genres: Comedy
Character mistake: "Blanco" Webb refuses parole on the grounds that, under Home Office rules, that would mean he had to admit to murdering his wife, a charge he vehemently denies. However, he accepts a pardon from the Home Office issued on the recommendation of the prison governor. Surely someone like Blanco, a man who quotes Home Office regulations by chapter, paragraph and verse, must know that a pardon is a remission of all punishment for a crime committed by the person being pardoned? By accepting a pardon he is admitting his guilt in exactly the same way as he would have been had he accepted parole.
Mackay: There are only two rules in this prison: 1 - do not write on the walls. 2 - You obey all the rules.
Trivia: Before Richard Beckinsale was cast, Ronnie Barker had suggested Paul Henry (Benny from the TV soap opera "Crossroads") for the role of Lennie Godber.