John le Carre's Tinker, Tailor, Soldier, Spy is one of the greatest spy novels ever written, and the BBC's adaptation of it, which I recently watched for the first time in more than ten years - and for the first time since reading the novel - is one of the greatest TV miniserieses I've ever seen.
The story is set in the early 1970's, when the British Secret Intelligence Service was in disarray. Its networks of spies in eastern Europe and Asia are being rounded up, and its agents shot or arrested. The long-time head of the Service, referred to only by his nickname, "Control," has determined that the Service has a high-ranking mole, but Control is dying, and losing his edge. He's narrowed it down to six possible candidates, all of whom are high-ranking career spies; World War 2 heroes with reputations beyond reproach. Control sends a trusted MI-6 operative to Checkoslovakia to meet a Check general who wants to defect, and who knows the identity of the Service's mole. But its a set-up, the kind of trap that a younger, sharper Control would have sniffed out. The ailing Control is 'retired' by the powers that be, and when his right-hand man George Smiley (played by Alec Guiness) suggests that the trap may have been set up by a mole, Smiley is discharged, too.
Eight months later, Oliver Lacon, the civil servant who oversees the British Secret Intelligence Service, contacts George Smiley and calls him to a meeting at a safehouse in the British countryside. As it turns out, a former British assassin has returned to England after going missing for months. He reports that, in his dealings with Russian spies in Portugal, he found out that the Soviet Union does, in fact, have a high-placed mole in British intelligence. There are only a few people in the Service who have the expertise to ferret out the mole, and Smiley, being the only person expert enough and out of the loop long enough to be beyond reproach, is the only one who can be trusted with the project. The catch: other than assistance of Smiley's protoge Peter Guillam, head of the 'scalphunters,' or hitmen, Smiley can't use any of the Service's employees, or any of their facilities, to avoid tipping off the mole. Without the use of official channels, Smiley has to uncover the mole by piecing together clues gained from interviews with retired, fired, and disgraced former intelligence agents, each of whom knows only a small piece of the puzzle. All signs indicate that Karla, the legendary head of Soviet intelligence, who Smiley once dealt with decades earlier when they were both mid-level spies working in India, is personally running the British mole, and may have been doing so since before World War 2. Since the mole - whoever he is - is somebody Smiley cut his teeth with and has worked with for more than thirty years, Karla and the mole know Smiley's strengths and vulnerabilities, as well as those of the other most senior members of British intelligence, making the detection that much more difficult.
The novel's byzantine plot is laid out in a way that's easy to follow, but that doesn't give anything away in an attempt to explain it to the audience. The BBC respects the viewer's intelligence - the story begins in medias res, and never condescends to its audience by spelling out what came before in excessive detail, and characters don't tell each other things they would already know. We are shown tradecraft - the nuts and bolts of how spying works - but we are not told. That the miniseries is able to wring so much tension out of a six-hour plot that mainly consists of a series of interviews and conversations is a testament to the quality of the acting, and that of the script. The tension arises both from the 'whodunit' nature of the plot, but also from our increasing understanding of the stresses and anxieties of working in intelligence. We learn how spy networks are built, and how double-agents work, and how double-agents can go wrong. A Soviet national, working in Britain as a spy, is 'turned' and persuaded or coerced into spying against the Soviets. He gives you information about what the Soviets are looking for in Britain - information you'd like to know - but you need to give him some secrets to take back to his handlers - otherwise his handlers will recall him (at best) or suspect that he's turned (at worst). If you don't give him important enough information, his bosses will get suspicious. But how can you be certain that the information you're giving him is as important as the information you're getting back. Are you turning a Soviet spy against his employers, or playing right into their hands? How much can you glean from the questions people are asking, even if you don't give them an answer? When you work with people who lie for a living, and who are trained for years in how to keep secrets and maintain a poker face, who can you trust?