The de-blinged room feels less glamorous than of old; all the theatre is now on the plate

Claridge's, Brook Street, London W1 (020-7107 8888)

As he emerges from the kitchen carrying two plates fashioned from tree bark, Simon Rogan's shell-shocked expression says it all. He's not in Cartmel any more. The honeyed, moneyed splendour of his new restaurant at Claridge's is a world away from L'Enclume, the converted forge in the Lake District where Rogan's reputation as the exiled genius of British food was tempered.

London's swankiest hotel is the last place you might expect to find the independently-minded Rogan. For years, he's been a lonely apostle in the gastronomic wilderness, preaching his hyper-local gospel to the pilgrims who made the trip (and indeed The Trip) to Cartmel. More recently, he's edged towards the bright lights, opening a two-year pop-up in London, Roganic, and last year, two restaurants in Manchester's Midland Hotel, an adventure chronicled by the BBC series Restaurant Wars.

Now Rogan has landed the Big Gig, taking over from Big Gordon at Claridge's. A brave decision on both sides, but a curious one. After all, how do you adhere to a doctrine built around the local, the foraged and the home-grown when you're in Mayfair? That's what we've all come to Fera (as in 'wild') to find out. In Restaurant Wars, Rogan was filmed waiting anxiously for a single national reviewer to show up. Here, the place is crawling with them. When I visit, a week after opening, the room has reached Peak Critic. No wonder he looks stressed.

The challenge hanging over Fera is unmistakeable. Rogan has met it with a confident and coherent response. Namely, just to keep on doing what landed him the job in the first place. His definition of local has expanded to encompass British, not just Cumbrian produce. But his devotion to rare-breed herbs and heritage oddities still runs through his menus like bindweed. If Dinner by Heston conjures up a fantasy of feasts in banqueting halls, Fera's menu, with its blewits, borage and beech leaves, evokes a lock-in in the Tudor kitchen garden.

There's no single break-out dish, no meat fruit or edible candlesticks. Just wave after wave of interesting, singular and often wonderful food. The flight of amuse-bouches which introduces the 10-course tasting menu is led by a conjuring trick of a dish, petal-garlanded puréed peas on a savoury pea wafer which vanishes on the tongue like a cloud. A silky umami-rich purée of Winslade cheese and potatoes holding a dice of duck heart and leek unfurls waves of complex flavour. Confited rabbit is fried into a crisp, tangled fritter and served with lovage emulsion; probably the star dish of the night, or rather, the star mouthful.

Mains are marginally more substantial. A pair of plump prawns, draped in lardo and sprinkled with petals (there's a lot of petals here), offer a briny rush of the seaside. A cup of mushroom broth, with an Asian salt-sweet intensity, comes with bread and bone-marrow butter. But the thrills are spaced further apart, and what should have been the centrepiece dishes – a two-way serving of Middle White pork with a mead reduction, and whey-poached brill in which the whey makes no discernible impact – fail to launch.

Rogan's style has settled since his early shock-and-awe experiments at L'Enclume, and most of the dishes stay on the right side of pretentious. But when a chef tells us that the seawater cream which accompanies a raw mackerel canape is made with seawater delivered directly from Cornwall, it all starts to feel a bit Last Days of Ancient Rome.

Fine-dining used to be all about luxe ingredients. Here, apart from the odd dab of caviar, the components are relatively humble. And it's hard to create a feeling of excitement out of seeds and herbs. The de-blinged room, now a muted slate-grey colour, also feels less glamorous than of old; all the theatre is now on the plate.

The constant tableside introductions to each new dish make for a bumpy experience. Fine if you've run out of conversation, but not so good if you're on a first date, as I was with my new friend Pippa, who'd generously bid for me in a charity auction. After three desserts and a flurry of wonderful petit fours, we'd used up our repertoire of eagerly anticipatory facial expressions. When we were invited to visit the kitchen, part of the Fera experience, it got even more awkward, though we duly trotted round, like slightly squiffy versions of Young Mr Grace.

It can only be a matter for celebration that there's an evangelically British restaurant at the heart of a famous London hotel. A decade ago, when I ate a dazzling meal at L'Enclume, no one in Britain was doing what Rogan was. But other chefs have caught up. And I'm not convinced his style will captivate the diners who go to blow their bonuses at Claridge's. Serving hedgerow-foraged food to hedge-fund managers – if he can pull that off, he really will have performed a miracle.

Food ****
Ambience ***
Service *****

Claridge's, Brook Street, London W1 (020-7107 8888). Three-course lunch £45; three-course à la carte £85; tasting menu, 10-course £95, or 16-course £125