These spies are middle aged (our main character, Smiley, is in his 50s), middle-class, and more prone to staring at files for long periods than they are to abseiling off the world's tallest building.
This isn't the action-thriller that make up the majority of modern thrillers, it's an old-fashioned thriller that does its job fantastically well by just ratcheting up tension, showing us the investigation, and playing things as realistically as possible.
John Le Carré, who wrote the original novel, recently gave an interview decrying the unrealistic nature of Spooke. And he should know, having worked for both MI5 and MI6.*
So what you have here is a portrait of foreign-intelligence operations as they actually were, bumbling, corrupt, and terribly dull, except when it isn't.
The actors are all on great form, the writing is sharp, and the direction and filmographt gave me flashbacks to my youth - terrible wallpaper, appalling clothes and all.
The basic plot is simple - there's a spy somewhere at the top of MI6, and George Smiley has to come out of retirement to find them. It's incredibly well constructed, telling large chunks of the tale through flashbacks without ever leaving me confused.
It's not an exciting film. You won't come out of it wanting to be a spy and save the world. But that's probably a good thing, and you won't regret it.
*TTSS is based upon the real life hunt for Kim Philby.