Life IS espionage .

"Why shouldn't there be a mole in the circus?" asks Control. That there very well could be, that there might as well be, that it's unthinkable that there may be -- these are all very good reasons for assuming that there is. Control is right, of course, but ferreting out the mole isn't a simple matter. cIt is a matter of excruciating and exquisite complication.

A "mole" is a planted agent, "the circus" Control's small circle of five seasoned gentlemen-spies at the tippy-tippy top of the British intelligence establishment. And the intricate and fascinating story of how the mole is caught, only after ramifications have run amok, takes six scintillating and delectable hours in "Tinker, Tailor, Soldier, Spy," the BBC serialization of a 1974 John le Carre novel. It begins tonight on public TV (Channel 26 at 8) and continues, weekly, through Nov. 3.

Absolutely antithetic to the glamorpuss school of spookery popularized by Ian Flenning's James Bond, Le Carre ("The Spy Who Came In from the Cold") portrays the spy's life as lonely and perpetually anxious; the spy, who can trust no one, serves as the quintessential existential citizen of a superpowered, petro-dollared, technocratic age. Director John Irvin and writer Arthur Hocraft have caught the crisp, cool, sinister wittiness of Le Carre's portrayal beautifully; they have been absolutely faithful in spirit and they have contributed complementary originalities of their own.

They have made of "Tinker, Tailor" one of the most madly atmospheric and enjoyably literate films ever done for television. "I've got a story to tell you; it's all about spies," says devious field operative Ricki Tarr (Hywel Bennett) at the end of chapter one. It's also all about betrayal, deception, distrust, ambition, expediency, treachery and the universal susceptibility of circuses to moles.

It is a television show to curl up with -- as a reader does with a very good book -- at times elusive and elliptical but worth every second of devout, spellbound attention. Just when you think you've utterly lost track of the plot and half the characters, everything snaps back into bracing, if fleeting, clarity. "Tinker, Tailor" proves not so much a merely captivating tale as an induced compulsion. A paranoid's delight. A thinking person's "Shogun." Chess with soul.

A glass of port on a chilly, rainy night.

Irvin's control over the situation is so methodical and shrewd it can make you laugh out loud with appreciation. He also has orchestrated an extraordinary cast into an unerring study of acting virtuosity from top to bottom. Top is Alec Guinness as Le Carre's aging, resigned, meticulous and humiliated George Smiley, whom we meet 20 minutes into the first chapter, after Control has sent agent Jim Prideaux (Ian Bannen) on a wild mole chase to Czechoslovakia. That's the last we'll see of Prideaux until part four, it is spoiling to tell you.

Guinness' performance as Smiley is positively balletic, elegantly deliberate in such simple gestures as the purposeful manner with which he puts on his glasses, as if they were going to make everything come to order, or the way he waves one hand in the air to signal a waiter for the check a an appropriately grim little bistro.

Implored to return from forced retirement to help bring the mole to the surface, Simley at first announces his grim reluctance, in a speech spoken by Guinness in such a way as to acquaint us with Smiley-to-the-very-depths during our initial encounter. "I've been reviewing my situation for the last half-hour of hell, and I've come to a very grave decision," he says. "After a lifetime of living by my wits an on my memory, I shall give myself up full-time to the profession of forgetting . . .

"I shall become an oak of my own generation."

Smiley had just escaped from a torturous dinner with that simpering old gossip Roddy Martindale (Nigel Stock) which ended with Roddy's insinuating farewell, "Everyone's love to Ann." Ann is Simley's faithless and deliriously indiscreet wife, and though references to her myraid infidelities keep cropping up in the darkest crannies of the story, we will not meet her until very near its end, after her significance in the story has been made woefully evident and after the mole himself, immediately upon being discovered by Simley, has asked with a classic lack of remorse, "Do you mind if I finish my drink, George?"

Ricki Tarr crawls out of the woodwork at the end of part one but doesn't really get into his tale of molery unti part two, when Smiley is brought in to interrogate him. "Now Ricki," says Smiley, "who are you at the moment?" For almost 32 minutes we flash back to Lisbon and Tarr's tale of a beautiful girl and her magnificent secret about the circus and its rodent problem.

In part three, Beryl Reld has a wonderful cameo role as a long-retired human memory bank named Connie, whose torch for Smiley still sputters around inextinguishably, to his complete disinterest. "Please kiss me, George." They kill. "Heigh-ho," she says."Halcyon days."

Members of the circus are made distinctive and ripe, expecially Bernard Hepton as the fussbudget Toby Esterhase, Michael Aldridge as Percy Alleline and venerable (to beat the band) Alexander Knox as the expiring Control.One of these might be the mole. And then again perhaps not.

As Smiley gets closer and closer to the truth, taking a number of provocative detours more or less in stride, the truth becomes less and less important. Not that one isn't dying to know which performer in the circus (given nicknames "Tinker," "Taylor," and so on) is guilty. No, no. But this isn't just an Agatha Christie whodunit. Smiley stumbles his intrepid way through so many webs of cross-purpose, moral ambiguity and intramural politics that the mole becomes not so much a pivotal culprit as just another doomed but enterprising pawn.

The tone of austerity and severity that Irvin maintains is sometimes breathtakingly bleak, yet there is an undercurrent of sardonic bemusement that is as formidable as Smiley's sly and seedy cunning. The thing is rich with savory details -- a colleague railing at Smiley that "This is no time to be WHIM-sical"; Smiley's flashback monolague to the Soviet agent Karla, who doesn't say one word during an interrogation in India in the '50s; Prideaux, now encamped in a trailer at a private school for boys, demonstrating what a damned nuisance bullet holes in the back can be; an agent singing "Ole Man River" to test out a bugging device at the scene of the mole's undoing.

For all the bitchiness of the dialogue and the pitch-black humor, "Tinker, "Tailor" is far more than a smorgasbord of surface pleasures. In some subtle, unnerving way, it truly speakes of the terror in the world. Recounting his treatment at the hands of enemy agents who had captured him, Prideaux notes in part five, "I hoped I'd go mad, but no, they knew how to stop that." This film keeps one in a state of being precariously and perilously on edge, but the sensation is quixtically exhilarating.

When it was shown in England last winter, this BBC-Paramount coproduction (acquired for public TV here by New York's WNET) became a national mania, much as "Shogun" was here recently, and was presented in the same form as on PBS, a one-hour chapter each week for six weeks. It would be awfully nice if PBS could later repeat the film without such vast spaces between installments. Previewing it in two three-hour viewings on consecutive days was anything but a chore, partly because there is a note of redundancy in the whole thing.

True, we are not used to television programs that absolutely refuse to let you leave the room, lest you return and be completely lost. But it's such a pleasure to find something on TV that commands this kind of concentration and rewards it so amply. Guinness is to star in another Le Carre adaptation for BBC-TV, "Smiley's People," and for those who get hooked on "Tinker, "Tailor," it won't be able to cross the Atlantic quickly enough.

You'll find me, for instance, waiting at the docks in nervous anticipation.