Ramona Marquez

Series three of this engagingly downbeat family comedy kicks off as Pete and Sue Brockman - the two of them outnumbered by their three children - go sightseeing in London with Pete's mother. Competing tensions are as usual caught precisely as Jake, now 14, Ben, nine, and Karen, seven, each have very different ideas as to what makes for a good day out, and aren't shy of letting their parents know about it.

Hugh Dennis and Claire Skinner play Pete and Sue but their thankless roles as parents in the comedy are mirrored in real life, because they more or less have to stand back and watch the children steal the show. Much of the dialogue is improvised and Karen (Ramona Marquez, who won Best Female Comedy Newcomer at last year's British Comedy Awards) comes up with most of the best lines, including a smart run-through of the dos and don'ts of political correctness. Perhaps these are topped, though, when Ben (Daniel Roche) gives a spot-on, if scatological, analysis of Gordon Brown's political prospects.

A few of the jokes - the confusion between lesbian and Lebanon, for example - are not in their first flush of youth, and the scene in which Dennis is left to clown around on his own is jarring, but otherwise this is a note-perfect sitcom capturing the gentle mundanity of middle-class family life in Britain today.

This semi-improvised sitcom continues to amaze in that it is an almost unheard-of example of a middle-class family sitcom that's actually very funny. Caustic, believable and refreshingly unsentimental, it boasts more good gags per episode than most mainstream BBC sitcoms manage in a lifetime.

A large part of its success, of course, is due to the natural performances of its child stars, particularly nine-year-old Ramona Marquez as the maddeningly inquisitive Karen. In this typically joke-packed opening episode, she drags the family - nominally led by selfless straight-men, Hugh Dennis and Claire Skinner - through a hectic historical daytrip to central London aimed at gathering research for her school project. She dismisses people who throw money into fountains as "idiots" and plays spot-the-lesbian with her anarchic brother Ben. Once again, it makes child-rearing look like an unyielding nightmare, but it's all the more hilarious for that.

If only because it centres so much on the precocious (yet, for the most part, just the right side of annoying) younger members of the cast, there's an obviously limited shelf to this series, centred on the chaotic everyday life of a middle-class south London family. So, who knows, this may well be both the first and last Outnumbered Christmas special.

If it is, it's comfortably up to the standard of the two full series we've enjoyed so far, as we descend upon the Brockman family - Pete (Hugh Dennis), Sue (Claire Skinner) and their unruly offspring Ben, Jake and Karen (Daniel Roche, Tyger Drew-Honey and Ramona Marquez) - on a less than blissful Boxing Day.

Parents-under-siege sitcom Outnumbered is a slow-burning hit that's steadily accumulated both favourable ratings and gongs (it picked up three British Comedy Awards earlier this month). Rightly so, because it's a rare beast: a comedy that captures the chaos of family life without lapsing into sentimentality. This festive episode, then, is a welcome taster for the third series next spring. It's Boxing Day in the Brockman household and, along with Santa, some burglars have squeezed down the chimney. As usual, precocious, pet-obsessed seven-year-old Karen (the remarkable Ramona Marquez) steals the best scenes - she's not only lost the school hamster under the floorboards, but takes it upon herself to make everybody else's New Year's Resolutions, with typical tact. Meanwhile, brother Ben (mop-topped tyke Daniel Roche) wreaks gleeful havoc with a mechanical hand and eldest Jake (the preposterously named Tyger Drew-Honey) is trying to find Awol grandfather Frank (David Ryall). The increasingly senile old goat couldn't be hiding with the hamster, could he? Parents Pete and Sue (Hugh Dennis and Claire Skinner) preside over this pandemonium with beleaguered bafflement.

In normal years, The Royle Family would be the sitcom special to be most keenly anticipated, but after last Christmas's aberration, "The New Sofa", judgement should be reserved on Caroline Aherne's latest reunion, "The Golden Egg Cup" (Christmas Day, 9pm BBC1). For unalloyed excitement, the 'Outnumbered Christmas Special' has me slathering at the chops. It's Boxing Day, and Andy Hamilton and Guy Jenkin's recognisably modern metropolitan family, the Brockmans, has been burgled - and I don't mean harassed parents Hugh Dennis and Claire Skinner getting every scene stolen from under their noses by the improvising child actors, Tyger-Drew Honey, Daniel Roche and Ramona Marquez.

Yes, that is Amy Nuttall in the opening titles tonight. The former Emmerdale and Celebrity Shark Bait star arrives at Babylon as the hotel's latest employee. Well, that's her story anyway. When Ben assumes she's the new receptionist she doesn't bother to correct him, even though the combination of her candy-pink lipstick and Ugly Betty-style braces make him recoil so squeamishly you'd think she was wearing a hat made out of used teabags.

But if he thinks her dress sense is bad, just wait till he sees what hotel owner Sam (Nigel Harman) is persuaded to wear at a baby shower tonight. Oh, Nigel, is this really what you signed up for?

Also checking in tonight is Hugh Dennis, who plays a comedian and an old flame of manager Juliet. And just to underline what a small world acting is, Hugh's on-screen daughter in Outnumbered is played by Ramona Marquez - the real-life daughter of Martin Marquez - Babylon's barman Gino.

Gino's overflowing with wisdom tonight as the hotel is the setting for the funeral of an Italian painter who was one of Babylon's most treasured guests.

As his widow and ex-wife trade black looks, the corridors of Babylon ring out with terrible Italian accents.

But then believability was never this show's forte - which could explain why Scottish actor Clive Russell is cast as the Italian corpse in another five-star farce.

Outnumbered lost out to The IT Crowd at the Baftas this year, which wasn't just baffling it was also a real pity, because Guy Jenkin and Andy Hamilton's winning portrayal of the minor absurdities of family life, and its brilliant, scene-stealing child actors, deserve proper recognition. In a repeat of series two's first episode, the family, including hapless mum and dad Sue and Pete (Claire Skinner and Hugh Dennis), is off to a wedding. As always they hover perilously close to being late as violence-obsessed Ben (Daniel Roche) debates if hitting someone who is attacking you with a shovel would be OK, limpid-eyed Karen (Ramona Marquez) locks herself in the bathroom and Jake (Tyger Drew-Honey) worries. It's achingly funny and packed with lovely moments, including Karen's remorseless quizzing of the increasingly unnerved bride, that always end with the grown-ups being outmanoeuvered.

Don't get too excited about the reappearance of Outnumbered. This repeat of the first episode of series two is just plugging an awkward gap in the TV schedules and the rest of the series won't be following. The family are at the wedding of Sue's cousin Julie - and young Karen (Ramona Marquez), the undisputed star of the show, is chief bridesmaid, quizzing the bride relentlessly on her dubious taste in boyfriends. While we wait for a third series to materialise, there are plenty of other TV shows where Karen's unique world view and unwavering style of interrogation could - and should - be employed. Hosting Have I Got News For You, standing in for Jeremy Paxman on Newsnight, interviewing suspects on The Bill... She's far too good to waste on just sitcoms.

Why Outnumbered is so good

You'll recognise that the children involved are startlingly natural and funny in their responses, of course, and that Ramona Marquez as five-year-old Karen effortlessly steals any scene in which she features.

There's good news for fans of Outnumbered. The unconventional family sitcom - which uses some improvisation - will be returning for a second series on BBC One at the end of September.

Hugh Dennis and Claire Skinner work well together as the hard-pressed parents of three small children. The kids themselves - Jake (Tyger Drew-Honey), Ben (Daniel Roche) and Karen (Ramona Marquez) - are terrific.

Written by Guy Jenkin and Andy Hamilton (who created Drop the Dead Donkey), the improvisational sections work surprisingly well, especially the off-the-cuff lines delivered by the kids. The lines are so good that at times Dennis and Skinner have to suppress their own wry smiles. In addition, Dennis is a gifted comedian who can also improvise, so it's a winning combination all-round.

The series became quite essential viewing last September, despite the BBC's bizarre idea of stripping it in two bunches of three consecutive episodes across a fortnight. This sort of show works much better with a more conventional regular weekly spot. Let's hope the BBC gets the scheduling right for the new series.