West Street, Central London

The Ivy is a sacred destination for London's smart set - what can possibly tempt them to entertain a new kid on the block?

What bad luck for West Street that opening practically next door to London's most famous restaurant has caused it to be dismissed as "the poor man's Ivy". Because the newcomer's pedigree is distinguished enough to earn West Street serious consideration in its own right. Its owners already run several of the capital's best modern restaurants, including Circus and The Avenue, as well as Kensington Place, (such a fixture with media types that after Princess Diana's death, one editor solemnly told me that crowds were lining up at Kensington Place to leave flowers.)

In the group's most ambitious project to date, a six-storey building has been refitted to encompass a bar, two restaurants and a boutique hotel – though with only three bedrooms, it's not so much a boutique as a changing room. On the ground floor, an informal, non-bookable canteen serves pizzas, meat and fish from a wood-fired oven; upstairs is the serious restaurant, offering a menu described as "English with an Italian accent", under the guidance of Kensington Place's Rowley Leigh.

Money has obviously been lavished on the conversion, which is in the ubiquitous 1970s' boardroom style – all brown leather and wood veneer – now apparently mandatory for any fashionable restaurant project. West Street had only opened a few days before our Friday lunchtime visit, and the finishing touches were still being applied. "That's a novel use for a razor blade in a central London restaurant," observed my guest, Neil, as we passed a man etching patterns into the frosted glass of the windows.

Neil used to be an Ivy regular, back when he produced a TV series fronted by Nigella Lawson. But he managed to affect a superior air to our fellow lunchers at West Street. "Who are they – Ivy overspill?" he mused, peering around the half-filled room. "Admen, I'd say. Certainly no celebrities." And with that, he adjusted his spectacles, held together with a clump of glue, and turned his attention to the menu.

This refreshingly direct document eschews exhaustive detailing of ingredients and methods in favour of simple, does-what-it-says-on- the-tin descriptions. Many of the dishes seem self-explanatory – langoustines with mayonnaise, for example, or rump steak with red onion salad. The more complex, such as lamb cutlets alla cacciatora, or monkfish with osso bucco, the staff prove admirably capable of explaining. An emphasis on seasonal ingredients, notably wild mushrooms, signals that the list will be regularly refreshed.

It was the fresh borlotti beans that attracted me to my starter, which paired them with octopus in a powerfully garlicky olive oil. Ordering octopus can involve a Captain Nemo-style wrestle, but these were sweet and soft, with the faintest inky aftertaste. "King scallops, ink sauce" was the terse summary of Neil's choice, a dish which proved to be built around a substantial (and over-salty) salad of radicchio and capers, in addition to three fleshy and perfectly cooked scallops.

So far the food was at least as good as my last meal at Kensington Place, when, in a triumph of hope over experience, I ordered grilled mackerel – there's a good reason why people have to be encouraged to eat oily fish. Mackerel makes an appearance on West Street's menu, but I wasn't going to make that mistake again, and opted for red mullet al cartoccio. On a French menu, this would translate as en papilotte – the fish is cooked in a paper bag, and arrives at the table still wrapped in it, like an upmarket doner kebab. In this case the puffy and heat-bubbled paper concealed a thing of beauty; pink fillets of opalescent fish, very lightly cooked, enclosed in a translucent wrapping of palest green leek, all swimming in buttery juices. It tasted as glorious as it looked, and made me question the wisdom of those stark menu descriptions – what similar wonders might they conceal?

Neil's calf's liver with pumpkin and sage was a relatively straightforward affair by comparison, but the menu's reticence misfired when it came to our side dishes. I'm not sure exactly what we were expecting from "creamed tomatoes with basil" but it wasn't three roasted tomatoes sitting in a bowl of hot cream. And "fried potatoes with spring onions" suggested something other than the thin game chips which arrived. You really don't want to end up with a plate containing both crisps and cream, however self-indulgent you might be feeling. Our fault, though, for not asking for fuller descriptions in advance.

Our sample selection from the shortish dessert menu revealed the presence of a pastry chef with a light touch. Cannoli al limone were crisp biscuit cylinders filled with lemon zabaglione, while a toothsomely light slice of hazelnut cake was served warm with a baked fig saturated in Marsala.

The wine list is built around mid-priced bottles, mainly young and Italian, and offers an interesting selection of wines by the glass, through which we reeled like a couple of shopgirls. "My definition of middle-class is someone who buys a bottle of wine and doesn't drink it on the same day," said Neil, as he chugged back his third selection of the meal.

Though there was nothing approaching the high-powered buzz that might be produced by a Friday lunchtime crowd at the Ivy, there was a certainly a quiet hum building up, and even a bit of tentative table hopping. The apparent lack of a non-smoking area, and the chirrup of mobile phones, contributed to the atmosphere in their own, not entirely positive, fashion. Service is expert and attentive from a team who exude the kind of empowered confidence which breaks down the "us and them" barrier. At around £60 a head, the bill was slightly higher than expected, but West Street is a valuable addition to the neighbourhood. An oasis of laid-back sophistication, even if you might not actually get to see Oasis there.

West Street, 13-15 West Street, London WC2 (020-7010 8600). Mon-Fri lunch 12-3pm, 5.30pm-midnight. All cards accepted. Wheelchair access