Last Night's TV - Episodes, BBC2; Shameless, Channel 4; Baking Made Easy, BBC2

There weren't many duff notes in Friends, the slick NBC sitcom that ran and ran from 1994 to 2004 and, for those of us with homes full of teenagers, is still running and running. But one of its duffest notes was the casting of Helen Baxendale to play Ross's British wife, Emily. Nothing against Baxendale, but amid all that sassy American humour, she seemed as flaccidly English as a stale Rich Tea biscuit surrounded by freshly baked chocolate-chip cookies.

In fairness, that was kind of the point; we weren't meant to warm to Emily. And Baxendale, deliberately, didn't get many killer lines. But it wasn't just that; whip-smart, wisecracking American humour just doesn't sound right emerging from a British mouth. For the same reason, Daphne Moon (Jane Leeves) was my least favourite character in the otherwise sublime Frasier. It's not that British actors aren't capable of wonderful TV comedy, just that the dialogue in the best US sitcoms is rooted in New York-Jewish traditions of razor-sharp put-downs and one-liners. Think Woody Allen and Neil Simon. On British television, comic dialogue has a different rhythm.

Anyway, all of this brings me to Episodes, in which Matt LeBlanc (dim, amiable Joey in Friends) plays a heightened version of himself in the latest example of what is rapidly becoming a TV genre all of its own: celebrities indulging in a game of double-bluff with us, playing themselves as slightly more neurotic and prima donna-ish than they actually are, which of course suggests that they're not neurotic prima donnas at all. Steve Coogan did this beautifully in The Trip recently, as did Larry David in Curb Your Enthusiasm. In Episodes, it is LeBlanc's turn. He plays Matt LeBlanc, hugely rich and successful thanks to Friends, who to the horror of married British comedy writers Beverly and Sean (Tamsin Greig and Stephen Mangan) is cast as the lead in the US version of their hit UK show. They wanted their British lead, a fruity RSC type called Julian (Richard Griffiths). But they get LeBlanc.

So far, so good. It's a great idea, with great opening credits: a script flying from London to LA. And there are certainly precedents for television successfully turning a mirror on itself; The Larry Sanders Show of blessed memory did it exquisitely. Moreover, there's something painfully real about British comedy writers being lured to LA by the sweet blandishments of network bosses and the promise of a Spanish-style hacienda in Beverly Hills, only for the semi-detached back in Chiswick to seem even more alluring once the dream starts to sour. You should hear the British writing duo Laurence Marks and Maurice Gran, who did the whole hacienda thing, on the subject. Yet I find myself unable to give a fat thumbs-up after the opening Episodes, and the problem lies with Greig and Mangan, or at least with their script. In a British context, they're both terrific comic performers. Greig was pitch-perfect as the hapless heroine in David Renwick's wonderful Love Soup. But here, trading waspish one-liners in the land of Jack Benny and George Burns, they seemed out of place. And although that's the whole point – that they are out of place – they should at least be talking like Brits, not Americans.

Still, it's early days. I have a feeling that Episodes will get better the more LeBlanc gets involved. And there have already been some lovely gags, like the friskiness that gripped Beverly and Sean when they saw that the vast bath in their rented Beverly Hills home could easily accommodate both of them, only for it to wear off while they waited for the damn thing to fill.

It's also a nice gag to have dishy Matt LeBlanc take a part that in Britain was played by Richard Griffiths, nobody's idea of dishy. I mean, can you imagine the lead in the US version of Shameless going to Tom Selleck? Actually, I think I can, although in fact it's William H Macy, which makes perfect sense, and yet I'll eat a three-week-old Pot Noodle with fag ash tapped into it if their Shameless turns out to be better than our Shameless.

That said, the eighth series, which began brilliantly last night, is to run for 22 episodes (the first five on consecutive evenings), which is much more them than us, and an indication of Channel 4's enduring faith in Paul Abbott's extraordinary gallery of grotesques, headed by Frank Gallagher (the peerless David Threlfall). Last night, Frank tried to come to terms with the terrible news that his daughter Debbie had been killed while serving in Afghanistan, and then with the terrible news that his ex-wife Monica had faked the news of Debbie's death, with the help of her gay partner, posing as a military policewoman. I wonder if the Americans are ready for a family as dysfunctional as the Gallaghers, who make the Simpsons look like the Obamas.

In the meantime, are we ready for another TV chef? In the case of Lorraine Pascale, I think we might be. Consider a hybrid of Nigella Lawson and Jamie Oliver in the form of a rather gorgeous black woman, and that's Pascale, the presenter of Baking Made Easy, an oddly prosaic title for a vehicle for such a glamourpuss and yet undeniably apt, for she did knock up some lovely-looking food with singular ease and a Jamie-esque tendency to "plonk it in" and "squidge it together", before sitting down to eat it with a tableful of her dearest friends, whom she'd quite conceivably never met before, à la Nigella.