Actor Richard Armitage (Lucas North) volunteered to be waterboarded as part of his research for his role in the series.
Harry Ferguson, in his memoir "Kilo-17", describes the procedure for ditching someone who recognizes a Spy from School as telling them to go away.
The show does not have any end credits, ending each episode with a trailer for the next episode and only showing a BBC production information screen. It does not list any cast/crew. Just the caption "A Kudos Production".
The show runs for 60 minutes, and in the UK airs on channel BBC1 which shows programs without commercials. The show has been re-named MI-5 for American broadcasts on the A&E network, and each episode is edited down to approx 44 minutes to include commercials in a 60 minute time slot.