Trinny and Susannah aren't in the same class as Nigella, more superannuated teenagers veering between strop and sulk than racehorse. But they're out of the same stable: they don't need second names; they're posh, of a certain age (46 and 48 respectively) and made their names on TV. They've also turned themselves into brands, and "do" humour, brilliantly. Readers might remember their fashion column in The Daily Telegraph's Weekend section, which, love it or loathe it, was a must-read for years. They took off into the fashionista stratosphere immediately afterwards with their TV series What Not to Wear, bullying members of the public into makeovers.

From Boom to Bust took up the story from there. It was a glorious spoof fly-on-the-wall documentary following the supposed collapse of their career. During this exquisitely funny offering, where small-screen setback was treated with the high seriousness of a Greek tragedy, every element of their career was mercilessly parodied.

We saw Trinny in a bath, covered in a hideous white facemask complacently discussing her diary. Cut to a taxi, where she was moving her colonic irrigation appointment so it would come after her "arse-slapping" slot with her masseuse (Think about it").

Cut to lunch with their agent, who told them not only had they failed to win a huge contract, but he was dumping them, too. Media names and celebrities appeared, as themselves, to mourn their decline: Dylan Jones (GQ editor), Lulu, David Furnish, DJ Neil Fox...

It got much worse, and much funnier. On to a golf and tennis trade show to promote their "magic knickers". "Susannah has a bit of a wobbly tummy," Trinny told the bystanders who had wandered up to their stall, hoiking up Susannah's dress to show how the magic knickers (deeply unflattering, flesh-coloured efforts) worked. Which is exactly the type of indignity they put their stooges through in their various makeover shows.

Will they, won't they climb back into the media spotlight? Perhaps they should get a makeover by Nigella. Now there's a thought.

Earlier this summer, fashionistas Trinny Woodall and Susannah Constantine posted a series of spoof films on the internet about their supposed attempts to get back on TV. A mixture of improvised and scripted scenes, spattered with F-words, they've been edited into a one-off comedy. It's supposedly modelled on Curb Your Enthusiasm, but at times the screaming and swearing make it more like something a group of drunken and/or stoned students would produce. That said, you have to admire them for mercilessly poking fun at themselves. "We used to be huge," screams Trinny in-between colonics, while Susannah spends most of her time in a cigarette- and alcohol-fuelled haze. It's fun to star-spot too: Lulu, David Furnish, Neil Fox and even a bemused Duke of Wessex make an appearance.

The Museum of Curiosity is also enjoyable, but very Room 101. John Lloyd is the professor of ignorance at the museum, which needs to fill a second, empty gallery. Sean Lock and three guests make up the "advisory panel". All are comedians and suggest some weird and surreal objects for the gallery. The result is pretty funny.

It just makes me wish the commercial sector would put more resources into this area of programming. But it doesn't have the safety cushion of the license fee, does it?

Radio comedies and fantasy tales aren't normally my cup of tea, but I enjoyed ElvenQuest, Radio 4'S Lord of the Rings spoof. It is well written, well acted and there are plenty of good lines to make you smile, although it is a little OTT on the canned laughter.

What I enjoyed - and here is the magic of radio - was sitting there painting the pictures in my head while listening. In my mind's eye this looked great.

It crammed in so many songs, they were never all going to be funny whilst the second hour-long results show confirmed what a seriously indulgent exercise it all was.

It's one thing getting Pete Waterman, Nikki Chapman and Neil Fox to send themselves up but having a parody of The Pop Factor without a Simon Cowell figure was a major cop out by Kay.

Having said that, Marc Pickering's performance as Leon, I mean, R Wayne, was brilliant - particularly his version of Ebony and Ivory with his ventriloquist's dummy of Stevie Wonder. The cameos by Rick Astley, the Cheeky Girls, and Macca doing the themes from Blankety Blank and Home and Away were better than most of Extras.

The one moment of comedy genius was Michelle McMammoth look-a-like cum-transsexual Geraldine's medley merging seamlessly from Born To Run to Born Free to Free Nelson Mandela and Umbrella.

This is Peter Kay's first major new work on TV for four years in which he spoofs - you guessed it - reality talent shows with characteristic accuracy and affection. Cat Deeley presents a 'live final' of an X-Factor-style extravaganza and it's down to three finalists - R Wayne, foursome 2 Up 2 Down, and Geraldine, played by Kay himself. The judges are Neil Fox, Nicki Chapman and Pete Waterman, and the results follow straight after a documentary about his record-breaking 2002 stand-up tour. If you are doing something else on Sunday night, you probably shouldn't be.

Peter Kay's first new TV comedy work for four years has been heavily trailed by Channel 4, and who can blame them? I still think Max and Paddy's Road to Nowhere was a brutal misfire for the popular (and undeniably brilliant) comic actor, but hopefully this will bring him back to comedy greatness. The explosion of reality talent shows might be an easy target for satire, but Kay, steeped in popular TV culture, should be able to get something from the show. Kay is Geraldine, a finalist on a talent show, hosted by Cat Deeley and judged by Pete Waterman, Nicki Chapman and Neil Fox. But is Geraldine keeping a deep, dark secret, and will 'she' win out in the end?