For many years, Mims was that rare creature: a neighbourhood restaurant of serious ambition. True, the interiors magazines weren't exactly queuing up to feature the decor, but what mattered, according to legend, was the food and the excessively generous price tag placed upon it.

In Barnet, they talked of nothing else. Six months ago the Egyptian-born chef, Ali Al-Sersy, who trained with the Roux brothers at Le Gavroche, decided he'd had enough of the conservative denizens of his north London neighbourhood and moved the operation down to a new site on the western reaches of the King's Road in London's Chelsea.

It is tempting to imagine that Mr Al-Sersy toyed with calling the new place South Mims, which is an hysterically funny joke if you happen to know the bottom end of the M1, but I doubt he did. He told me he named it after a magazine used by doctors called Mims, which lists medicines and their uses. 'After all,' he said, 'food is a kind of chemistry.'

I think he is doing himself down here. In Al-Sersy's hands, and at these prices, food is a kind of alchemy: £14.50 gets you two courses; £18.50 gets three, of clever, extremely well-executed food. True, the interiors magazines are still unlikely to be queuing up - the walls are decorated in a dizzying array of queasy pastel colours, giving Mims the look of a Mediterranean pizza parlour to which young people travel on farty mopeds to meet up and snog each other. There is also some garishly original artwork which only a mother could love. But these details, along with the eager staff, simply add to the eccentric charm.

All that matters is what's on the plate. A starter listed as 'seared squid, chilli, garlic, ginger, black noodles' failed to mention the generous serving of king prawns. The fish had a grand charcoal tinge to it and the black ribbons of noodles, coiled into a witch's hat, burst with a chilli nuttiness. An open ravioli of a light crab mousse came with a crisply seared tranche of salmon on a light, fresh jus of coriander and ginger. Perhaps the crab filling could have been a little denser or the pasta a little heavier to lend ballast to the dish, but such quibbles simply prove the seriousness of the food.

No such questions with the main courses. I had roast duck, which had been so well rendered it suggested the skin had been removed, cooked down and then returned, because it had all the golden meaty bits you want, rather than the fatty bits you don't. As with my starter, the saucing here was very light, tinged with anis and orange. A cliché? Perhaps, but only because it is true. A massive serving of lamb rump was seared and pink, and with it sat a disc of moreish roast potato.

Puddings read simply, but are not. A light, pod-marked vanilla and white chocolate mousse was housed in a cylinder of thin dark chocolate, laid about with tart redcurrants still held pertly on the branch. More pleasing still, a heart-stopping, artery-clogging apple cheesecake, with little balls of cinnamon-infused apple on the side of the plate, arrived beneath a wispy bonnet of vanilla candyfloss.

There is a short list of about 20 wines, starting at £9.50 for the serviceable house bottles and none, bar champagne, topping £20.

So, are there any problems with Mims? Yes, one. On the Thursday evening we went only three tables were filled, and that, to me, is ludicrous. I have no idea whether the staff - or the kitchen - could cope with a rush, but I beg you to give them a chance to find out.

· Mims, 541a King's Road, London SW6 (020 7751 0010). Dinner for two, with wine and service, £60