Last Night's TV: Grandma's House / BBC2 <br/> Inn Mates / BBC3 <br/> Identity / ITV1

A family portrait that hits home

Remember the Labour Party's "special adviser", Jo Moore, who spin-doctored her own political downfall by suggesting that 11 September 2001 was a good day to bury bad news? The broadcasting equivalent is the entire month of August; a good time to bury bad sitcoms, and other stuff in which the suits – or perhaps, more accurately, the denim jackets – have lost faith somewhere between the raising of a commissioning editor's thumb and the final click of post-production.

Accordingly, all sitcoms making August debuts should be regarded with circumspection if not outright suspicion, and last night there were two, one of which, Grandma's House, went and undermined a time-honoured tradition by being rather good. Or at least, good in parts. It was a curate's egg of a half-hour, not that a curate and his egg offer the best metaphor for a show about a loving but bickering family of east London Jews. In fact, it is a singularly ill-fitting metaphor, the expression "curate's egg" originating in the old Punch cartoon about a curate who was too timid to complain about a bad egg he had been served. There would be no such timidity at any table of Jews worth their salt beef. Even a visiting rabbi would spit out such an egg.

Enough eggs already. Grandma's House revolves around the simple idea, one that dates back almost to the birth of television comedy, of different generations of the same family arguing in a front room. Steptoe and Son did it to great effect, so did Til Death Us Do Part, so did The Royle Family. In some ways, Grandma's House is The Royle Family with chopped liver. In other ways, it is Seinfeld removed to Gants Hill. And the nod to Seinfeld is evident in the character of Simon (Simon Amstell), the presenter of a TV comedy panel show about music, which – just as Jerry Seinfeld played a stand-up comedian called Jerry, a mildly fictionalised version of himself – is precisely what Amstell, the co-writer of Grandma's House with Dan Swimer and erstwhile presenter of Never Mind the Buzzcocks, is in real life. Or was. Indeed, in last night's opening episode Simon announced to his family his intention to quit his TV show, much to their dismay. "In my kalooki group that's all we talk about," lamented his grandma (Linda Bassett).

The other obvious parallel with Seinfeld is that Jerry Seinfeld made it through nine seasons of that phenomenally successful show rarely ever being more than engagingly wooden as an actor. Good acting was the preserve of his brilliant co-stars and so it is here. Amstell barely seems to try to act, just issues his lines semi-mechanically wearing a half-smile, just as Jerry did.

Still, it didn't matter in Seinfeld and, strangely, it doesn't matter here either. Amstell, aided by the sensible decision not to run a laughter-track, somehow makes a virtue of his self-consciousness, and in any case, there are enough pitch-perfect performances, notably from Rebecca Front playing Simon's divorced mother, Tanya, and Samantha Spiro as his aunt, Liz. It helps that the writing, too, is often pitch-perfect. Tanya is being courted by Clive (James Smith), whom Simon loathes, but who is considered highly eligible largely on account of a 42-inch plasma TV on which "you can see every hair of Noel Edmonds's beard". And when Simon's grandpa (Geoffrey Hutchings) breaks the news that he has cancer (an unwittingly poignant detail, given that Hutchings died suddenly last month), it is questioned on the basis that "years ago he found a lump on his testicle and it was a raisin in his pants".

Just as a wandering raisin can be mistaken for a testicular lump, so can a promising first episode be mistaken for a good new sitcom, and I wouldn't like to commit myself too soon. Besides, there are reasons why London-Jewish humour is far less familiar to us than the kind of New York-Jewish humour exemplified by Neil Simon, Woody Allen, Seinfeld and Larry David (whose Curb Your Enthusiasm also has loud echoes in Grandma's House). It is no accident that the Jewish humour British audiences know best and love most has historically been imported, mordant and razor-sharp, from the United States. Nor is it any accident that Jewish characters in British sitcoms are, for the most part, pretty forgettable. It is more than 40 years since Never Mind the Quality, Feel the Width, and not even the warm glow of nostalgia does it any favours.

Still, will anyone remember Inn Mates even critically in 40 years' time? Or in 40 days' time? Here is a sitcom that, on first viewing, fits all the preconceptions about debuts buried in the dog days of summer. The opening episode was as embarrassing to watch as it possibly was to act in, although there could be no faulting the cast for effort, and it wasn't their fault that a narrative appeared to have been eschewed in favour of a series of disconnected sketches that relied for laughs on spectacles such as that of a pair of fat police community support officers getting stoned. Drugs, sex and alcohol loomed large throughout, in fact, and while I'm all for at least two of those vices, the whole package was enough to make you weep for The Good Life.

As for the final episode of Identity, it made me weep for what this series might have been. The subject of identity fraud is rich with dramatic potential, but Identity degenerated into an overwrought and not-especially-thrilling thriller. A shame.