TELEVISION Faith in the Future (ITV)

The sitcom spin-off that makes good use of domestic appliances.

The sitcom spin-off, a kind of genre within a genre, has a more specific task than most television comedy. It not only has to meet the basic requirement of being funny in its own right, but also has to live up to or surpass the original off which it spun. The fate of Grace and Favour, which regrouped the cast of Are You Being Served? in a hotel, serves as a terrible warning to anyone planning to rejig an old comedy.

As Frasier and Porkpie, its recent, slightly less distinguished British equivalent, have proved, the better spin-offs come about by isolating from a successful but now defunct sitcom one character deemed strong enough to bear the weight of his own vehicle. Second Thoughts, a will-they- won't- they-wed sitcom, reached a natural terminus after 50 episodes. Its spin- off, Faith in the Future, thrives by fishing for laughs in an entirely different pond - the mother-daughter relationship in which either one or the other is manless.

Unsurprisingly, in the wake of AbFab, this happens to be a currently popular source of comedy. Faith in the Future does little to silence the echo, with Julia Sawalha carrying on from Second Thoughts as the contrary daughter she seems perennially destined to play. When Faith ends you can switch over to Channel 4 and watch the practically symmetrical Dressing for Breakfast, in which the only variation is that the daughter is neurotic and not the mother.

ITV comedy has a tradition of locating the lowest common denominator, but there's something sprightly and unforced about Faith in the Future. In last night's episode, Faith (Lynda Bellinghan) succumbed to the menopause, and the running joke about middle-aged female self-obsession somehow flaunted the law of diminishing returns. It helps that Jan Etherington and Gavin Petrie are a mixed-doubles script-writing team, equipped to meld sympathy ("I want to hold a retirement party for my ovaries") with something sharper (Hannah furtively crumbling an HRT tablet on to her mother's pasta, in lieu of parmesan).

Typically, there may be two orgasm jokes, but they don't step on each other's toes, because one is verbal and the other visual. "You don't want to have sex; you just want to have a moan," says daughter Hannah. "I thought that was sex," replies Faith. Then, in an unabashed quotation from When Harry Met Sally, she cools her hot flushes by rubbing her neck with ice in a cafe. Much use was made of the fridge: in one of several clever camera tricks, Faith is filmed from inside it, fanning herself to cool off, and later we see her battily replenishing it with loo rolls. It's a household appliance common to most sitcoms, but here plays its part in two different gags about the same physical condition.

The only weak link in the script is Hannah's colourless boyfriend, who's about to disappear to Australia the way every character does that the scriptwriters are trying to dispose of. You can be sure they won't be making a spin-off out of his experiences there.