You know you're getting old when tormented British spies from the early-1970s start looking younger.

At 29, Tom Hughes, who plays Joe Lambe, messed-up hero of the 1972-set Cold War thriller The Game, is only two years younger than Michael Caine was when he prowled to stardom in The Ipcress File. Stand the two performances side-by-side, though, and they come from different planets. Hughes is highly watchable, but it takes a while to forget he's acting. When Caine's laconic agent entered a room full of "superiors", you instantly felt the chip on his shoulder.

Watching The Game and thinking back to the great, weary and wretched cold warriors British pop culture produced between the 1960s-80s, I was reminded of the differences in attitude between the new and old Poldarks. The current series, with its soft slow-mo and come-hither Timotei vibe, is a different sensation to the 1970s reading: all distance, hard lines, and bare, ground-down, grown up emotions.

I say this as a fan of the new Poldark, and The Game is fun, too. But if you're a lover of that era's hard spy fictions, you have to push them aside to give this series a chance. Above all, you have to stop thinking about John le Carré, which gets difficult, when the programme is so desperate to make you think superficially of le Carré all the time. Proffering the stylised 1970s that exists in a wash of browns and orange, where the light seems filtered through malt whiskey and stewed British Rail tea, it's as if the production designer had been traumatised by the 2011 movie of Tinker, Tailor, Soldier, Spy, and is trying to recreate it as a form of art psychotherapy. But while these sets are sturdier than anything on TV in 1972, Edward Woodward's Callan would rip through them, with a bitter ferocity this show couldn't contain.

Mostly, the faults, and the fun, of The Game are down to its creator, Toby Whithouse, who previously brought us Being Human. His set-up is the one le Carré and Len Deighton used time and again: in MI5's resentful corridors, agents get wind of a KGB plot, and simultaneously begin suspecting there might be a mole among them.

Whithouse mounts a tribute act to the old le Carré adaptations. The greatest hits ­- dead drops, wiretaps, tradecraft talk and chalk line signals, everyone watching each other - are here. But it's like hearing a cover of Joy Division. The notes are present, but there's nothing of the echoing atmosphere. He catches the spirit, loses the feeling.

The Game is terrified of the stately pace of the Alec Guinness George Smiley series: those long stretches of nothing but aging faces talking densely in shabby rooms. Whithouse is nervous, too, of such narrative opacity. For spies, this lot spend a dubious amount of time telling each other what they think, and explaining things they all already know.

And yet, over-egged as it is, once the seedy, paranoid old shadow game is running, it still gets its hooks in. Amid the Cold War themepark, Whithouse employs an old-fashioned TV touch that works: each episode leads to another KGB sleeper, a Guest Double Agent Of The Week, meaning turns from dependables like Steven Mackintosh and the terrific Rachael Stirling, each slightly altering the flavour. You never believe anything is in danger, but it's fun. More than a genuine Cold War throwback it's like a modern BBC spy show doing a period special: Spooks In The 1970s House.

The Game begins on BBC Two on Thursday at 9pm