But past histories, rivalries and friendships make it far from easy to pinpoint the man who has chosen to betray him and their country.
The dour Smiley's search takes him back to a botched operation in Budapest and tests his ability to put his personal life aside in his hunt for the spy.
In the end he must set a trap to flush out the man who is leaking the high-level information.
Based on John le Carre's spy novel Tinker, Tailor, Soldier, Spy is a heavily layered hunt with every move leading to the next, much like a chess game.
The all-star cast keep us guessing at every stage and by no means is it easy to detect the identity of the villain.
Tinker Tailor Soldier Spy
(M), Universal
Rating: 3 / 5 Stars