Geales, 1 Cale Street, London SW3

When I recently polled people about the top 10 best things about the North for this paper, proper fish and chips came pretty high on everyone's list. Proper fish and chips means a steaming cod the size of a small beer-battered child, and fat chips reeking with the sting of vinegar. Proper fish and chips are eaten on or within sight of a prom, and served by a woman in a pinny with a greasy bun and an enormous bosom. Most importantly, they come with white bread and bottled ale and leave you with change for a go on the waltzer. I was dubious, therefore, when I learnt about a swish new fish and chip shop... in Chelsea.

Geales may lack the prom, the beer and the enormous bosom, but it must be getting something right. When Mark Fuller and Andy Taylor (the team behind Embassy in Mayfair) bought the original Geales in Notting Hill in 2007, locals and regulars were up in arms (they all went "tut" and "crikey"). The place had been open since 1939, and many of them seemed to have been stewing in chip fat over long lunches there ever since. The critics were neatly divided into those who despaired at the move upmarket (Matthew Norman; Tracey McLeod) and those who welcomed the peeling of generations of grease from the kitchen walls (AA Gill; Terry Durack).

Clearly, there have been enough of the latter for the team to open this new branch in Chelsea Green (turn right at Lamborghini and keep going past Chanel, sweetie), with an almost identical menu (down to the retro Art Deco font), décor (dark wood floor; slate-grey walls; black-and-white fishing scenes; futuristic space loo) and clientele (three fat old Etonians with napkins tucked in their collars; two women who could buy Bridlington if they pawned their rings; a table full of French people, noisily relishing their cod & chips; four lunching ladies with spoilt little screeching darlings who would probably be happier at Harry Ramsden's).

The charming waiters lack the pinnies etc, but one has an exceptionally fine moustache and that's almost as good. "I am sure that you are going to enjoy it," says another when I enquire about the seaside pick & mix (£3). He's optimistic: the plump mussels, tasty squid and solitary prawn (I did tell him that I can't bear them: cockroaches of the sea) come guarded by a long, pink, suckered tentacle which is... not nearly as hideous as it looks. The dill pickles (£1) turn out to be big fat gherkins with a fancy name, but there's nowt wrong with a big fat gherkin. And the wine that he recommends, a 2009 Picpoul de Pinet Saint-Peyre (£22.50) is perfect for the food, and mercifully towards the cheaper end of the list (£14.50 to £125). It's not ale, but it is always a nice surprise when posh restaurants manage the apparently spectacularly difficult task of simultaneously having the wine on ice and letting you keep it on the table.

Emboldened by a swift half of Picpoul, I opt for the fish soup, £8 (the menu bucks the current "hand-sourced" trend by being not very big on description), and my lunch date, having torn his hand on a rogue nail in his chair leg, asks for the dressed crab (£11) to cheer him up. Only then does the waiter remember that it's run out (curse those screeching darlings).

Fortunately, a hot smoked-salmon salad with pear and walnuts (£8.75) dries the tears, and the rich, tomatoey fish soup is fantastic, not too fishy, and huge. There's not enough cheese in the cute little Gruyère/croutons/rouille combo that accompanies it, but when is there ever enough cheese? And, I don't know how the Chelsea set would put this, but... well, I'm still burping fish. But it's worth it.

For non-fish eaters, the menu offers three types of steak, and macaroni cheese. But it would be wrong not to try Chelsea's best attempt at sustainable (Cornish) cod and chips (£11.75). The house salad with avocado and cherry tomatoes (£6) is apparently too big for a side dish, so we order spinach and some perfect fresh-pea-tasting mushy peas (£2.95 each). They're so exciting that my lunch date forgets that his scampi (£9.75) doesn't come with chips, and has to eat mine. The bugger.

And the fish and chips? Perfectly crisp; perfectly fluffy. I can't fault it (damn it). The tartare sauce is bland, there's no vinegar with anything and I have to ask (how gauche!) for ketchup, but I must admit that this is a dish to rival east Yorkshire's finest. It is also tiny, of course: The Magpie in Whitby this ain't. It's good, though. Very good. For Chelsea.

7/10

Scores: 1-3 stay home and cook 4 needs help 5 does the job 6 flashes of promise 7 good 8 special, can't wait to go back 9-10 as good as it gets

Geales 1 Cale Street, London SW3, tel: 020 7965 0555 Open for lunchand dinner daily. £95 for lunch for two, including wine and service

More fish and chips

Magpie Café

14 Pier Road, Whitby, North Yorkshire, tel: 01947 602 058

Don't be put off by the queues (or uncomfortable interior) – if you're looking for the fish and chips of the gods, this legendary harbourside chippy remains the place to go

Aldeburgh Fish And Chips

225 High Street, Leiston, Suffolk, tel: 01728 454 685

Ideally eat fish and chips from this seaside chippy sitting on the shingle beach, beside the upturned fishing boats

Graveley's Fish & Chip Restaurant

8-12 Cheltenham Parade, Harrogate, North Yorkshire, tel: 01423 507 093

This smart and pleasant town-centre spot is an excellent place for fish and chips, but offers a broad-ranging fish menu, too

Reviews extracted from 'Harden's London and UK Restaurant Guides 2010'. www.hardens.com