ट्रिविया

Peter Firth is the only cast member to appear in every episode of the show, as well as star in the follow-up film Spooks: The Greater Good (2015). He does not, however, appear in Spooks: Code 9 (2008).

The availability and iconic status of certain London landmarks made them popular locations throughout production. Exterior shots of Thames House, the headquarters of MI5 were used in many episodes to establish the location. However, due to the security risks involved with filming such a location, London's Freemasons' Hall was used for scenes where actors were entering or leaving the building, and for some internal locations. This same location was later used as Thames House in Torchwood (2006), Children of Earth episodes. Establishing shots of the SIS Building were also used for scenes involving members of the Secret Intelligence Service or MI6. Other landmarks commonly used included the London Underground, and the Millennium Bridge. Many scenes are filmed in and around the Docklands, especially Canary Wharf, Rotherhithe, London Bridge and Greenwich (including The Old Royal Naval College), as well as the More London development. Some of the army barracks were filmed at Merchant Taylors' School, Northwood.

For much of the first series Matthew Macfadyen's character (Tom Quinn) wears dark glasses, this was actually due to a burst blood vessel sometimes just visible.

The lamp shades hanging from the ceiling of the Grid in season 1 are actually bins from Ikea turned upside down.

None of the episodes had any on-screen credits (until episode 3.6) when first broadcast. That's why everyone is (or should be) listed as (uncredited).