Simon Amstell, type-cast as himself, is the star and co-writer, with Dan Swimer, of Grandma's House. It can best be described as The Royle Family relocated to North London, converted to Judaism and featuring a former host of Never Mind The Buzzcocks amongst its cast of characters. Basically the show comprises of thirty minutes of nagging, whining and kvetching, lapsing into the vernacular between three generations of very extended family.

Mum's odious suitor Clive, a cardboard box salesman obsessed with cooking-times for meat, is thrown in for good measure. The action, such as it is, is mostly located in the living or dining room, although at one point there was a short excursion upstairs to a bedroom.

It may not sound thrilling, but Grandma's House is worth watching for the terrific performances, the gag-packed dialogue that ricochets around the walls, and for a terrific, understated turn from Amstell, providing a calm, snide, cynical centre to the emotional storm.

t's hard not to curb your enthusiasm when you enter Grandma's House (sorry). Does the world really need another self-referential comedy that riffs off its central character's public persona? If the second episode of Simon Amstell and Dan Swimer's sitcom is anything to go by, yes. Not only are the characters well drawn, but the one-liners are cracking. Tanya (Rebecca Front) goes into a weird state of Jewish mother overdrive that even Woody Allen might balk at writing: "You can have my pubic hairs if you want them!" Tonight, Simon tries to scupper her marriage to Clive.

I expect genuine grandmas - the kind you might see on The One Show knitting sweaters for penguins - would really enjoy Simon Amstell's new sitcom. And how could they not when its central character is a nice Jewish boy who's good to his dear old mum Tanya (Rebecca Front)? In episode two, he's ­actually bought her a car.

A very small car, admittedly, and it's yellow. But still a very thoughtful present - it's not even her birthday. Simon bears gifts for several members of his family, while totally ignoring his auntie Liz's birthday - to much hilarity.

Amstell and his co-writer Dan Swimer have cleverly sketched a family forced by blood to be nice to one another, without sharing anything else in common.

Auntie Liz (Sam Spiro) is a mass of quietly seething sibling rivalry whose life is just one crushing disappointment after another. "I've lost two stone now," she says as she celebrates finally hitting her target weight. "Wonderful!" beams her mother encouragingly. "How much more to go?"

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.

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