Deliberate mistake: In the scene where the ministers are all crammed into the train carriage if you look over Jim's shoulder there is a sign ("Notice" "In case of Fire" etc), while the headers are in English the actually paragraphs are written in gibberish.
Yes, Minister (1980)
1 mistake in season 1
Starring: Nigel Hawthorne, Derek Fowlds, Diana Hoddinott, Paul Eddington
Genres: Comedy
Sir Humphrey Appleby: It's always a victory of the heartless over the mindless.