Alison Steadman

Gavin wants to call it quits with Stacey

Although Alison Steadman and Larry Lamb, his co-stars in Gavin & Stacey, have set their hearts on seeing the award-winning BBC comedy series turned into a film, Matthew Horne tells me that it would be "a terrible idea."

The BBC's hit comedy Gavin & Stacey was back with its winning formula of gooey romance, slapstick angst and recurring logistical challenge of getting a vast ensemble of Essex and Welsh people into the same room without it seeming odd. Perhaps that's its genius. This week they solved it with a christening party, adding yet more characters. Here was Nessa's dad and Smithy's mother (Pam Ferris, looking like she'd slept in a skip), and Ewan Kennedy was cracking as the new baby, Neil - strapped facing outwards on Nessa's back. "That's so I can smoke," she drawled.

The Welsh steal this show, led by Ruth Jones as Nessa - gnomic, brusque, experienced - alongside her spiritual opposite, Bryn (Rob Brydon), garrulous, sentimental and unworldly. I don't know about the Billericay element. Alison Steadman is a bit of a pantomime grotesque as Gavin's mum, and Smithy's Byronic laments for Gav - now installed in his new job in Cardiff - are fast losing their charm. I'm all in favour of a man expressing his feelings but if Smithy were my best mate I think I'd have to move farther than Wales.

Where Little Britain produced bizarre, gross-out comedy, Gavin & Stacey is a very traditional sitcom. It works in the manner of Dad's Army or Birds of a Feather - the eponymous leads, played by Mathew Horne and Joanna Page, provide a focus in front of a background populated by slightly grotesque caricatures, such as Rob Brydon's camp and simple-minded Uncle Bryn. Now for this third and final series, James Corden's Smithy is still living in Essex while Gavin (his best friend) and Stacey (Gavin's wife) have moved to Stacey's home town of Barry Island in South Wales. As the familiar characters reunite for the christening of Smithy and Nessa's son Neil, viewers who are new to the series (which has previously won two Baftas) may find that this opening instalment is not as immediately likeable or accessible as they might wish. Who, after all, would choose to spend time in the company of Gavin's shouty mother Pam (Alison Steadman) or Stacey's offensive best friend Nessa (Corden's co-writer Ruth Jones)? But as this first episode continues (next week's second is much funnier), it becomes obvious that these weirdly dysfunctional families makes a kind of sense - and that their ludicrous travails are no more ludicrous than most family's. So it's all very sweet, even if there's none of the innovation or edginess you'd find in The Office or The Thick of It.

You can't blame BBC3 for constantly repeating its best-ever programme. Here's yet another chance to laugh along with a long-distance relationship conducted in Billericay (his home) and Barry Island (hers), complicated by the young lovers' ditsiness and their weird families and friends. The starry supporting cast (Alison Steadman, Rob Brydon, plus writers Ruth Jones and James Corden) provide the vulgar belly laughs, all as larger-than-life loons who never quite tip over into caricature, thanks to the earthy, affectionate script.

Welcome return for John Finnemore's situation comedy about a struggling small charter airline. It's blessed with a classy cast, Roger Allam, Benedict Cumberbatch, Stephanie Cole as Carolyn, the boss, and Finnemore himself as her perennially perky son Arthur. And today Alison Steadman arrives as Carolyn's sister. They haven't spoken for years. Arthur hasn't bothered to think about that as he's planned a cheery birthday trip for them all. To Helsinki. He's booked it on his Mum's credit card. And she thought it was proper business.