One-O-One: Inside a tower in west london, you'll find an ambitious chef recreating the finest flavours of his native Brittany

One of the most intriguing dishes at the reinvented, redesigned and relaunched restaurant One-O-One is baked for one hour at 60 degrees. Intriguing, because it is the dish itself: a firm plank of sea salt that forms a foundation for a sampler of oysters.

The salt comes from Brittany, as do the oysters – Tsarkaya from Cancale – and indeed, the chef himself, Pascal Proyart. Even the butter here comes whipped with Breton seaweed, giving it a briny, savoury twang.

It's all about the sea at One-O-One. Proyart's new menu is divided into low tide (seafood), from the shore and beyond (seafood and more), high tide (fish) and sea and earth (surf '*'turf combinations). Everything comes in scaled-down "petits plats" portions, and diners are politely advised to order three dishes, so as to leave some room for dessert.

One-O-One is a restaurant with serious intent. You can see it in the fine glassware, plush napery and groomed staff, who are formal and helpful, if slightly humourless. The luxuriously comfortable dining room is the shape of a slip sole, decked out in what designers call "oceanic shades", and the adjoining, open bar has been designed to res-emble an oyster, with a central silvery share table representing the pearl.

The size of the dishes may have scaled down, but technique has not. Ingredients are often represented in various forms, including vogue-ish gels and frothy foams. So a starter of moulded red tuna tartare (£12) comes with a craggy outcrop of soft shell crab tempura, a little sushi roll topped with wasabi sorbet, a thin, crisp seaweed baton, and three little cubes of pink pickled ginger jelly. The sushi rice is then injected at the table with a soy and wasabi sauce via a miniature pipette. Busy, yes, but it tastes fresh, bright and focussed.

The mighty Norwegian red king crab, of which Proyart is the UK's leading ambassador, appears in five different dishes. For a starter of crab with sauce vierge (£11), the centre canon of the leg is very gently cooked and cut into three trunks, strewn with perfectly defined, fleshy little cockles and served with a warmed herb-based vinaigrette. It tastes simply as crab should taste – not bland, cold and muddy, but with sea-salty clarity and light-as-mousse texture.

The wine list speaks fluent French, but talks only to those comfortable with paying over £50 for a bottle. Two wines that slip under the net are a peachy, bone-dry 2006 Schloss Gobelsburg Gruner Veltliner from Austria for £31, and an elegant, minerally 2005 Prieure St Come Chablis at £39.

An unremarkable-sounding red mullet bouillabaisse (£10) is the catch of the night. A single fleshy red mullet fillet squats upon a midden of chopped Brittany shellfish, including winkles, whelks and razor clams, as a smooth, heady bisque-like broth is added at the table, ready to soak into little seaweed-flecked croutons.

A pan-roasted Norwegian halibut is over-cooked, which suggests the kitchen is still adjusting cooking times to suit the smaller serves, but a foray into sea and earth lands me a dish of butter-roasted Brittany blue lobster tail and roasted sweetbread that shows perfect timing. Linked by a saffron-spiced carrot compote and a foamy vanilla emulsion (£17), the rich, broad, voluptuous flavours teeter on being overly sweet but are saved by the liferaft of finesse. As Alain Ducasse says, there is no such thing as genius in the kitchen, there is only the work.

To end, a frothy coupe Liegeoise of dark Manjari chocolate and salted caramel ice-cream (£6) disappears in seconds.

There is a precision and delicacy of touch at One-O-One that is in keeping with the chef's ambition to "go for a Michelin". It is a bit pricey and a bit poncy, but Proyart takes seafood to the sort of heights more commonly seen in his native Brittany, at, say , Olivier Roellinger's Les Maisons de Bricourt or Jacques Thorel's L'Auberge Bretonne.

That is clearly where his food should be eaten, with sea views, waves and screeching gulls, rather than in a land-locked Knightsbridge hotel. But at least it has the power to transport you there.

16/20

Scores: 1-9 stay home and cook 10-11 needs help 12 ok 13 pleasant enough 14 good 15 very good 16 capable of greatness 17 special, can't wait to go back 18 highly honourable 19 unique and memorable 20 as good as it gets

One-O-One, Sheraton Tower Hotel, 101 Knightsbridge, London SW1. Tel: 020 7290 7101

Lunch and dinner daily. Around £150 for two, including wine and service (business lunch £15 for 2 courses)

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