When John le Carré wrote the novel in the early seventies, and when BBC television adapted it in the same decade, Tinker, Tailor, Soldier, Spy seemed less a work of fiction than a heady dose of current affairs.

The book read, and the miniseries played, with the immediacy of a leaked document revealing a brutal truth: that the world of Cold War espionage was a tawdry exercise in moral relativism; that the battle was waged not for any concept of good but merely over degrees of evil; and that the warriors were mostly mean-minded nerds bent over desks in a benighted bureaucracy.

On le Carré's pages, the spy game owed nothing to James Bond and everything to Franz Kafka – dangerous to the body, perhaps, but absolutely perilous to the soul.

Story continues below advertisement

Nearly 40 years later, this superb remake has the inevitable look of a period piece, a smoke-filled rendering of things past. However, thanks to Tomas Alfredson's direction, a taut screenplay, and a uniformly brilliant cast, the film also retains its contemporary relevance, doubling as a crisp reminder that the ethical ambiguities of today's geo-political climate are hardly new, that there was never anything simple about the simple dialectic of the Cold War.

Necessarily, the feature-length version prunes the narrative detail from the novel, but is also careful to add its visual equivalent. For example, Alfredson, a Swede best known for his moody work on Let the Right One In, opens with a close-up of John Hurt's weathered face, a convoluted matrix of deep fissures and crags as tangled as the British intelligence service he heads. Hurt plays Control, leader of the "Circus" that is MI-6 – actually, now, the former leader.

Having learned of a suspected mole planted by the Soviets smack in the Circus's centre ring, Control dispatches an agent to Budapest to discover more details. There, what is ostensibly an action scene unspools at the same measured but deadly pace, a lethal languor, as everything else here.

The job gets botched and Control gets fired, leaving the senior managers – Percy Alleline (Toby Jones), Bill Haydon (Colin Firth), Toby Esterhase (David Dencik) and Roy Bland (Ciaran Hinds) – to scheme their way up the corporate ladder. Like the muddy browns and dull greys that dominate the sets, or the nicotine that stains fingers and fouls the air, their inveigling ambition is not a pretty sight.

Story continues below advertisement

Still, rumours of the double agent persist, ascend to the upper echelon of government and result in George Smiley, who was axed with Control, being lured out of retirement to spy on his fellow spies. With his thick glasses, plaid muffler, mild paunch and milder manner, Smiley resembles an avuncular accountant.

In the BBC series, that's exactly how Alec Guinness portrayed him, as an essentially decent if disillusioned man violated by circumstance. But Gary Oldman augments the mix with a remnant of muscularity, a hint of menace, the strong suggestion that, even as a young blood doing field work in the fifties, Smiley came by his dark side naturally – he didn't have many illusions to lose.

His search begins and, from there, the plot settles into its basic task of ferreting out the mole. At its narrative centre, then, the film is an old-fashioned whodunit; yet it's the thematic circumference that dominates – the whole clotted and Byzantine atmosphere of the place, the loyalties betrayed and the betrayals compounded.

To that end, Alfredson repeatedly poses Smiley beside windows, staring out through the deceptively transparent pane at other entanglements as cross-hatched as Control's face – at a jumble of power lines, a maze of railway tracks.

Story continues below advertisement

But the real labyrinth, of course, are the offices of MI-6 itself, a rabbit warren of doors and hallways cluttered with the low-tech apparatus of the era: teletype machines, reel-to-reel recorders, paper files in metal cabinets.

Only rarely does Alfredson venture beyond this diseased house, although always to pointed effect. A trip to Istanbul is every bit as chilling as that earlier venture to Budapest. And a visit to a posh private school, where a former "scalp-hunter" is now teaching, is a telling reminder of where and how British intelligence recruited – young or old, it's the same boys club.

Telling, too, is a recurring flashback not found in the book, a kind of period piece within the period piece. It's a return to a boozy staff Christmas party, where the principals are more youthful and the times more innocent. Or are they? At first, apparently.

But each recurrence sees the scene grow thicker in sinister subtext, until the flashback becomes the movie-in-miniature with the same encapsulated warning: The past is never simple and not even past – it always sows the seeds of the present.

Story continues below advertisement

Tinker, Tailor, Soldier, Spy