Preview by Steve Bennett

It's a confident comedian who surrounds himself with inveterate scene-stealers; but that's what Greg Davies has done yet again with Man Down.

Following the tradition set by casting the much-missed Rik Mayall as his father in the first series, the third run kicks off with Steven Berkoff as psychotic Serbian Mr Klackoff, the caretaker at the school where Davies's character Dan works and a sinister, unpredictable force that rips through the episode.

The ever-compelling Berkoff isn't the only larger-than-life character in the show. Rosin Conaty's Jo is as naively bonkers as ever, while Stephanie Cole returns as the formidable, no-nonsense Nesta

Series three also introduces us to Daedalus,played by Tony Robinson, a love interest for Dan's mum (Gwyneth Powell). We only get the briefest of glimpses of him in episode one, dressed like a Poundland Quentin Crisp but with sideburns you could buff your boots on. But there's enough of a flash of his inflexible authoritarian ways to intrigue about his future role.

Tony Robinson">

He's certainly into children being obedient, and that includes 45-year-old ones. Not that Dan has anything like an adult lifestyle – lazing around in a messy, smelly bedroom, grumping at his mother and hating the obligations of school, he's still a feckless teenager at heart.

But for all these people tormenting Dan, no one does it more than Davies and his co-writer Mike Wozniak, who also plays Dan's straight-laced mate Brian. In another brutal script they heap ever more humiliations on to the hapless, useless teacher.

The plot here could, on the face of it, have come out of Sitcom Writing For Dummies. Dan's facing a disciplinary hearing so breaks into the headmaster's study to steal the evidence with, as they say, hilarious consequences.

But it's the execution of the idea that makes it. After hatching the plan with Jo and Brian acting as the devil and angel on his shoulder, Dan's subjected to some punishing physical ordeals as he goes about the heist.

This episode treads a thin line between comedy and horror, from the mishap with a fence that's more watch-through-your-fingers painful than jaunty slapstick (below) to the menacing, sociopathic presence of Mr Klackoff. The painful payoff to the adventure is only saved from being grisly by the cheapness of the prop.

Yet despite Dan's uselessness and deceit, we root for him. Maybe we recognise such traits in ourselves, even if writ smaller, or maybe because downtrodden Dan is vulnerable at heart, and made warm by Davies' engaging performance.

A bolder decision than conceding laughs to the larger-than-life supporting cast would be taking Dan out of school – which, surprisingly, appears to be the way this series is heading.

For the classroom scenes provide so many of the best lines in the sharp script, often from the kids in Dan's drama class. fter being told to make up a play about something worthy, one pupil delightfully trills that he's going to play a ninja. 'A ninja with Aids,' a classmate mutters under his breath.

It's delightfully inappropriate, as so much of the writing is.

• Man Down returns to Channel 4 at 10pm tonight.

Review date: 13 Jul 2016
Reviewed by: Steve Bennett