Launceston Place, 8/10

Telephone 020-7937 6912
Address 1a Launceston Place, London W8
Open Lunch, Tue-Sun, noon-2.30pm (3pm Sun); dinner, all week, 6.30-10.30pm

If its new owners have one particular fond fantasy for Launceston Place, it must be a blue plaque above the door bearing the legend, "Diana ate here. A lot." So she did, in frequency if not in portion size, even though fusty, chintzy LP was always the Queen Mum to its stablemate Kensington Place's media-savvy people's princess a mile or so to the north.

The sign I would prefer to nail to this pretty town house's exterior, meanwhile, would feature "HazTel", in luminous red paint on a skull and crossbones background. For these owners include Sir Terence Conran - and history teaches us that although his ventures tend, in greyhound terms, to be fine trappers, they soon lose stamina and heart, and then end up plugging along at the rear to the wistful serenade of betting slips being shredded.

And this latest one certainly franks the first half of that form guide, albeit some disagree. The ever magnificent Brian Sewell, who used to love Launceston Place for its maiden-aunt-up-in-town-for-a-spot-of-shopping genteel shabbiness, has expressed his umbrage at the fanciness, not to mention schmanciness, of the reinvention. I appreciate Sewelly's pain - all change is for the worse, as someone clever once said, even when it's clearly for the better. Yet those of us with vague memories of a complacent and mediocre restaurant may feel inclined to agree more with Heraclitus, who said that everything is in a constant state of flux, so we may as well get used to it (I translate loosely).

Whichever philosophy appeals, D&D Holdings (the Conran Group as was) has wedged up to create a lavish experience at what are, at least for now, very decent prices. The nook-and-crannyish room, which snakes away at the back to allow the sort of privacy every royal needs when briefing against her husband's family, has been done out in Green & Black's dark-chocolate brown, the flower displays are glorious and the banquettes incredibly comfortable. It's a touch dated, in a 2004 edition of Wallpaper* kind of way, but inoffensive and relaxing for all that.

If being cosseted is your bag, then this is your place. The highly trained French staff almost outnumber the punters over whom they hover with intent, so much so that they make you nervous about pouring so much as a glass of water for yourself for fear of activating sirens such as those that greeted poor, radioactive Karen Silkwood. And if the service is designed with a certain inspectorate in mind, so, too, is the food - the poncey, homemade crisps at the start and the pre-dessert freebie near the end frame a none too subtle plea for the Michelin imprimatur, perhaps so they can swiftly raise the prices to more typically Kensingtonian levels.

That star won't be long in coming, either, because the young cook, Tristan Welch (who came from Petrus, which has two of them), has enough talent to render the tedious orthodoxies of the age - the cat-sick foams, baby-food purées and so on - less irksome than usual. Two of us went for the cheaper menu at £24 for three courses, while a growing boy of our acquaintance heroically overcame the ear infection that had kept him from school to go for the longer, grander one at £37.50.

The pick of the starters was neither a lovely, springy warm salad of garden peas with lightly fried Ayshire ham, nor the creamy quail breasts flash-fried at a trolley in front of us in enough cognac to leave that boy a touch drowsy. Both were great, but the undisputed champion was my spider crab risotto with lashings of garlic butter, which came covered by the shell to enable a waitress to remove it as if it were a dome (I nearly had my wrist slapped for attempting the lift myself) - this was a sensationally rich, savoury and delectable dish for a cheapo menu, and worth a return visit on its own.

Before the American woman showing off her iPhone in deranged detail at a nearby table had time to use it to call Esther Rantzen, the boy recovered his poise to set about chunks of deep pink Gressingham duck, cutely sprinkled with crackling-style duck shreds and served with radish and turnip slices. ("The duck's very good, if a bit salty," he said, "but I'd swap all the other stuff for potatoes.") My free-range chicken, poached and then baked to give it texture, had the unexpected bonus of tasting like chicken, and came with a vibrant avocado purée. And the missus enjoyed her fillet of beef with smoked bacon, quail eggs and cheddary mash - a gratifyingly expensive cut to find on a set menu that concluded by offering an impressively delicate rhubarb crumble and a caramel parfait with a lively blood orange mousse. The boy finished off with a splendid millefeuille of new season's strawberries with pistachio.

And yet, and yet... Such prices are all too often hiked by 25-35% within 0.03 seconds of the last review appearing in print. Not only that, but starting well is a much easier trick than sustaining the form, as Trap 4 in Friday's 7.39 at Wimbledon would confirm. For now, though, this is as luxurious and linger-worthy a set meal as you're likely to find anywhere for a quid less than a pony. But be quick, and don't forget the HazTel.

The bill

2 set lunches @£24 £48

Crab risotto

Chicken poached & baked

Rhubarb crumble

Pea & ham salad

Fillet of beef

Caramel parfait

1 à la carte, three courses £37.50

Quail breasts

Gressingham duck

Strawberry millefeuille

1 Coke £3.50

1 glass sauvignon blanc £6.75

Subtotal £95.75

Service @ 12.5% £11.97

Total £107.72