The Spa stars the incomparable Rebecca Front as the long-suffering head of a health, beauty and fitness centre, where staff and clients alike prove a constant source of grief, inconvenience and aggravation. The writer and creator is Derren Litten, who hit comedy pay dirt with Benidorm, ITV's most successful sitcom in years. Cynics might say ITV's only successful sitcom in years.

Despite the involvement of Front and Litten, I still didn't expect much from The Spa. Possibly because the basic premise reminded me of the late and lamentable The Brittas Empire, but more likely because the show is being broadcast on Sky Living. In all my years of flicking up and down the endless array of channels on offer, I have never found reason to stop and dally at Sky Living, or even work out what it was there for.

Well, knock me down with a gym ball, but The Spa is rather splendid. The characters are fun, the storylines outrageous, and the script fearless and successful in its pursuit of big out-loud laughs.

Rebecca Front holds centre stage as Alison, former Leighton Buzzard slimmer of the decade, whose imperious management style comprises brutal insensitivity complemented by a total absence of tact. Front fends off scene-stealing turns from a talented cast, most notably Frances Barber as boozed-up best mate Ginny, Tim Healy as the handyman who is quite literally too big for his breeches and Litten himself - it's your show, mate, you cast yourself in it - as an overweight, wheelchair-bound fitness instructor.

There are one or two funny moments in this second edition of Derren Litten's new health-club comedy - Alison (Rebecca Front) and her peculiar sleeping arrangements; Davina (Debbie Chazen) trying to realign the chakras of a flatulent punter; and Cheryl Fergison as insulted customer Ms Wylde being fobbed off with a colonic. The performances make this watchable.

But I'm still waiting for Frances Barber, as Alison's stable-owning mate Ginny, to get something worth her spit. And the addition of a Polish chef/plumber called - wait for it - Bolek seems to be heading nowhere and is just another sign of the woolly randomness of the script.

Rebecca Front is almost unrecognisable as blonde health club manageress and "Leighton Buzzard's slimmer of the decade" Alison Crabbe. Cheryl Fergison (EastEnders' Ev) plays an affronted punter, Bergita (sounds like "big eater"), while Tim Healy is a well-endowed handyman barely contained by his shorts. And the ever-arch Frances Barber pops up as... well, her role isn't clear in this first episode; maybe next week.

So, a promising ensemble for a sitcom that reads like a retread of The Brittas Empire, is a tad short on laughs and perhaps needed more sessions on a cross trainer before public exposure. Still, The Spa is the brainchild of Derren Litten, creator of the heroically bawdy Benidorm, which I won't hear a word against, so it could well take off in coming weeks. And this time, Litten has put himself in the frame as an aerobics instructor in a wheelchair.

Benidorm writer Derren Litten launches a new comedy with the help of an outstanding cast including Rebecca Front and Frances Barber. Alison (Front) is Leighton Buzzard's slimmer of the decade and manager of The Spa, a supposed haven for the stressed but actually rather shrill and brightly coloured. The formidable Barber plays her boozy friend Ginny. No previews were available, but if those two can't provide the plumpers and fillers to Litten's trademark jolly-but-flawed scripts then no one can.

Friday Night Dinner throws us a curve ball this week. Mum's on crutches. Dad must cook.

The horror! Even before he's walked through the door, Adam has a near-death encounter with family acquaintance Sheila "Bitchface" Bloom (Frances Barber), her husband and their precious Mercedes.

Poor Adam. And it's his birthday dinner, too.

It's all topped off with a present from Dad - a history in praise of the SS.

Wonderful present for a Jewish son, gasps Mum.

Dad gets himself in more hot water when he lets slip that his youthful relations with Bitchface may have gone beyond the one date he's previously admitted.

But the Goodmans close ranks when they encounter Bitchface later in the evening when her snobbery sets off a sort of comedic Tourettes.

They just can't help ­themselves. And we wouldn't want them to, either.

The glorious Frances Barber guest stars in this episode: she's an old flame of dad Martin (so bumping into her again seriously ruffles Jackie's feathers) and has such an obsession with her Mercedes that it routinely sends Adam and Jonny into fits of giggles. It's also Adam's birthday, which Martin ruins by cooking an hilariously awful dinner and giving his son the worst present you could possibly give a young Jewish boy.

Tonight's Friday Night Dinner, chez the Goodmans, is cooked by hopeless dad (Paul Ritter) as mum (Tamsin Greig) is immobile after spraining an ankle. Of course, it's a disaster as the meat is rigid with overcooking and makes terrible noises when dad tries to carve. "Should meat squeak?" the family wonders aloud. Poor Adam - this is supposed to be his birthday treat, along with a coffee table book on "heroes of the SS", a thoughtful gift for a young Jewish boy from his dad. It's another gloriously silly episode of Robert Popper's utterly endearing sitcom, which strays into Curb Your Enthusiasm comedy of embarrassment territory when dad bumps into an old girlfriend, the brassy Sheila Bloom (Frances Barber). Or Bitchface, as she is ungallantly known. Sheila is obsessed with her Mercedes to the delight of her tormentors, who find new and inventive ways of sniggering at her - not behind her back, but right in front of her face. It's packed with minor pleasures, including mad neighbour Jim and his supernaturally calm dog, and a piece of farce involving grandma in unsuitable clothing.

Robert Popper's soft-centred but sharply observed sitcom about a suburban Jewish family continues. Tonight it's hapless elder son Adam's (Simon Bird) birthday. Barmy Martin (Paul Ritter), his father, makes a disastrous attempt at a celebration roast. "Is it clay?" asks Grandma. The family decamp to the local Chinese where they run into blousy, Mercedes-obsessed neighbour Shelia Bloom (a sparkling Frances Barber). Popper's deft plotting and a top-notch cast make this a small-scale gem.

If anything was going to put you off your Ferrero Rochers over Christmas, it had to be The Fattest Man in Britain, ITV's comedy drama about a man in an orthopaedic armchair eating himself to merry hell. Timothy Spall looked dangerously at home in the title role as Georgie, with comedian Bobby Ball admirably cast as his "manager", Morris, turning up with a cabful of Japanese tourists eager to take pictures and lay their hands on the big man's folds. "I would ask you to respect Georgie's private zones," said Morris (though, frankly, you imagined these people might get enough blubber at home). Frances Barber completed the homely trio as Janice, who came in every day to shovel Georgie's meals together and grease his legs, which was as attractive as it sounds.

With Caroline Aherne co-scripting, there was as much pleasing northern drollery as you'd expect amid the ill-lit claustrophobic clutter and junk food and trash TV familiar from The Royle Family, though admittedly the oxygen tank looked ominous.

Things took a turn when a crew of youths was sent by the social services to tidy the garden and Amy - a pregnant teenager on the run from a violent boyfriend - ended up moving in. Aisling Loftus was excellent as the underfed, beaten waif looking for a father figure and finding it in kindly Georgie. There was a worrying moment, in his late mother's bedroom, when you wondered what kind of a comedy this was turning into... but no, Amy was soon settling in, cooking and tidying up, nibbling a dark chocolate Magnum with Georgie (not the classiest of product endorsements), helping Janice with his pig-sized legs and restyling his terrible 80s mullet - an early clue that he hadn't been out in 23 years. That's how long it had been since his mum died. "It's like I was eating for her," Georgie confided. "Like there was an angel on my fork."

All was well until a rival barrage balloon from Birmingham challenged Georgie to a TV weigh-in and Morris - aided by locals arriving with mountains of pizza and bakewell tarts - set to bulking him up for the contest. Amy - now almost as big as Georgie (well, not quite, but who remembered she was even pregnant?) - railed against the freak show that would surely kill him.

Events were channelled into a poignant denouement, but when the baby died and Amy called it a day with Georgie, it didn't feel like tragedy. Even when Georgie rose from his chair and struggled down the street to see her, it was more Love Actually than love. There was a late attempt at profundity with a short disquisition about the desire to make failure look like success. "If I'm not the fattest man in Britain, what am I?" cried Georgie. "I'm just a fat man!" It was a great line, but it just made me think that inside this broadly entertaining drama was a sharper, less funny one trying to get out.