At the insistence of my housemate, I once read a thriller by a Spooks writer. It was no John le Carre. A bit that was annoying was the hero was given a two-part GPS co-ordinate, 54321, 12345 or whatever on a scrap of paper that takes him to an office block. The narrator then tells us that because he is a spy, he has a special GPS receiver that can give him altitude information, so he know which floor his target is on. WTF? He didn't have a Z-axis co-ordinate to work with!
Rubbish In, Rubbish Out. There is a reason I've watched the Wire, and Alec Guinness in Tinker Tailor, but not Spooks.