Or not, stock footage and sets with recognisable English 'stuff' like red telephone boxes and buses, and black taxi cabs to save money! I remember seeing an episode of something - not "24" but similar - and none of it was shot here, you could see the Houses of Parliament, the London Eye, Buckingham Palace and Nelson's Column in pretty much every scene - especially where they didn't belong! - but the architecture and everything else was entirely wrong. We'll see!