Quote:* After Osborne has been assassinated, an MI5 agent comes over to Tom and Harry in the churchyard and whispers something in Harry's ear, what he actually says is, "The goose has landed." This had to be repeatedly re-shot as 'Matthew MacFadyen' and Peter Firth couldn't stop laughing.

* The second episode of the first season, where Lisa Faulkner's character dies by being tortured with a deep fat fryer and subsequently being shot in the head, was the most complained about television show in Britain in 2002. Likewise the second episode of the second season, in which the plot dealt with Muslim suicide bombers, was the most complained about television broadcast in the UK of 2003.

* The boiling fat which killed off Lisa Faulkner's character in episode 2 ("Looking After Our Own") was actually cold tea.

* In the first series the interior of Thames house was filmed in a college in Kensington, the night shots of the beach shown in Episode 2 ("Looking After Our Own") were actually filmed on the cobbled courtyard outside the university.