This spy film really is a puzzle.

There’s the plot for one thing – it’s about the search for a mole within the British secret service, with recently retired agent George Smiley (Gary Oldman) drafted in to work out which of the four men it could be.

There are a lot more details too complicated to go into here, so you’ll need to pay attention and learn the lingo (see our cheat sheet, right).

The other puzzling thing about TTSS is its slow pace and old-fashioned style.

Yes, events are set in the 1970s, but the movie doesn’t need to feel like it was made then, too.

Not to say this film needs explosions, car chases or shoot-outs (we can see Mission Impossible: Ghost Protocol for that).

If you stick with it, and manage to infiltrate the complex storyline, there’s a gripping tale to be told – it just might require a second viewing to really find it – but soldier on and this spy flick will deliver.