Among the criticisms rightly levelled at the BBC are that its commissioning editors are overcautious, unimaginative, unadventurous and over-reliant on star names and proven formulae.

So I really didn’t have much hope for The Wrong Mans (BBC2, Tuesday), the latest vehicle for the painfully ubiquitous James Corden. Since Gavin & Stacey — which I know we’re all supposed to have cherished beyond measure — Corden has become as inescapable a part of the BBC furniture as David Jason was in the Eighties, or Robson & Jerome were in the Nineties. If Corden had pitched a script based on the Albanian telephone directory, I’m sure the BBC would have commissioned it like a shot. As indeed they did when Corden proffered something nearly as ominous: a comedy thriller set in and around Bracknell.

Bracknell? Oh dear. Wasn’t the so-dull-it’s-funny theme done to death when Ricky Gervais set The Office in Slough? Comedy thriller? That’s even worse. The reason the comedy thriller is the most reliably disappointing genre ever invented (apart from maybe jazz funk) is that each half of it continually undermines the other: the jokes and pratfalling prevent the build-up of tension; the necessary darkness, death and menace make the humour look tasteless and intrusive.

How come, then, that The Wrong Mans has turned out to be one of the most inspired and reliably enjoyable things on TV this year? Let’s start with the premise: Mathew Baynton plays Sam, the second most useless worker at the world’s dullest town council; and James Corden plays the worst — Phil Bourne, an insufferable attention-seeker from the postroom loathed by everyone for his irritating banter, his desperate courting of popularity and his pathetic fantasies of becoming an adventure hero. Somehow, these two abject losers find themselves embroiled in the script of a violent, pacy, convoluted thriller involving kidnaps, executions and deadly Russian assassins. How? Best not to ask. Just let yourself go and enjoy the crazy ride.

This week’s episode provided arguably the best set-piece yet, at the home of a deranged billionaire Russian art dealer on a mission to retrieve a MacGuffin-type music box, whose purpose has yet to be explained but I’m not sure it matters: the main thing is that the dealer is a coke-snorting, fizz-swilling, gun-toting megalomaniacal homosexual who thinks Sam is the rent boy he ordered for one of his insane, unbridled soirées and that Sam must be humiliated and dance, shirtless, for the groping dealer’s delectation to buy time while Phil scours the mansion for the music box. I wonder whether Corden got the idea for the hectically involved plotline — which he co-wrote with Baynton — during his stint in Richard Bean’s smash-hit West End farce One Man, Two Guvnors. ‘When we started writing it, we realised why people don’t do that. It was really hard to write! A lot of man hours just working out plot. Everything has to be taut, moving on at the right pace,’ Baynton has observed. Precisely. Farce is an incredibly difficult genre to pull off because you cannot allow your audience a moment’s space to question the outrageous scenarios into which the characters are helplessly propelled. But when it’s handled as deftly as it is on The Wrong Mans, it leaves you gasping with bemusement, exhilaration and glee.

Corden’s light comedy skills needed no introduction. For me, though, the series’ revelation has been Baynton (who appeared briefly in Gavin & Stacey but is better known as a member of the brilliant Horrible Histories troupe), who has the rare gift of making nerdy, dull and useless seem simultaneously heroic, sympathetic and full of hidden depths. This matters, because we have to believe in him as a halfway credible on-off love interest for Berkshire Council’s fast-rising talent Lizzie Green (a very beguiling Sarah Solemani), whose hand we are all surely rooting for him somehow to win by the end.

Part of the series’ genius lies in this deft interweaving of the stultifyingly mundane (the council’s excitement over their potential new slogan: ‘Bracknell. Small town, big future’; a Jamie Oliver aubergine lasagne adulterated with peas) with the glossily implausible, like some weirdly hilarious accident in which James Bond smashes his sports car into one of David Brent’s strategy meetings.

It’s so jarring it almost doesn’t work. At one point, Phil and Sam are rescued by the deus ex machina of a macho, supremely capable British secret service agent (Dougray Scott) in a black Mercedes. Their lives depend on him, yet being such relentless prats, neither Phil nor Sam can ever quite bring themselves to treat any situation with the seriousness it deserves. ‘Thanks, Dad,’ blurts out Phil, threatening to pull the rug from under the whole preposterous thriller plotline. But then another bloody and very real death occurs, and you’re off on the rollercoaster once more, hanging on for dear life, enjoying every moment.