Recycled Script: There have been a few cases where the exact same strip was reran a second time. Several times, they didn't even change the date, two of which were less than a week apart.
The TV series:
Enforced Method Acting: Scenes in the third season with regulars going undercover as neo-Nazis were covertly filmed at a real far-right-wing political gathering in Belgium. The fairly-left-wing actors' fear and discomfort weren't wholly simulated.
Fan Nickname: The show was named "Between the Loins" or "Between the Sheets", due to some sex scenes that at the time were a bit more explicit than usual in the genre.
Franchise Zombie: Tony Garnett subsequently said that he hadn't wanted to do the third season but was pressured into it by the BBC.