The Fountain: Fortnum & Mason has given traditional fare a deliciously knowing tweak at its refitted Fountain eatery

The Fountain, Fortnum & Mason, 181 Piccadilly, London W1, tel: 020 7734 8040

Barbara Cartland could not have designed it better. David Collins' impertinently pretty makeover of The Fountain restaurant is so chic, so darling, and so pink that it's my new favourite dining-room in London.

Fuddy-duddy old post-war Fortnum's has returned to a gilded age of crinolines and reticules, perfectly matched bays and phaetons, and coquettish ways with fans. Everything is grandmotherly delicate, the pink edged with the palest of blues. Grandmother's best porcelain is on display behind glass, the chandelier drips with crystal, the columns are of antiqued mirror and the come-hither bar is of pink marble. It is a room that is designed to turn women into duchesses and men into gentlemen.

This re-plumbing of The Fountain is just one corner on the lower-ground floor of an elegant facelift for Britain's most famous grocer, recently officially unveiled by Prince Charles to mark its tercentenary. My wife and I have just run down Piccadilly from the Tube in the pouring rain; the phaeton seats and matched bays are otherwise occupied, but the room transforms us instantly into the smouldering Lord Rotheringham and the devil-may-care Lady Dorinda, dining, scandalously, à deux. And at the grocer's!

The menu is a pleasing list of Brit-French comfort food, full of the sorts of things one instructs cook to prepare for a simple repast. As with the more contemporary 1707 wine bar downstairs, Shaun Hill (of the legendary Merchant House) has been called in to consult, and together with head chef Mark Blatchford, has whipped up a litany of fish and chips, eggs Benedict, ham-hock terrine, lamb chops, chicken in a basket, and an apparently legendary Welsh rarebit.

Having never seen the charm of Welsh rarebit, I can't say that I am going to start now, faced with two slices of soggy cheese on toast for 12. The ham-hock terrine (6) has far more charm, a mosaic of juicy porky jambon persill in parsley-studded jelly coming with a good dollop of zingy piccalilli. Lady Dorinda adores a wing of skate (16) that is as fresh as a breath of sea air, drenched with nut-brown butter, tiny little shrimps and a few diced roasted potatoes.

But Lord Rotheringham loses his heart to the steak-and-mushroom pie (12), because it is a real pie, not one of those stews-in-a-bowl-covered-with-a-pastry-lid pretenders. This is Fortress Britain, with walls of pastry so thick and sturdy they should have a drawbridge installed to allow access to the rich, flavoursome, fall-apart meat. A moat of dark, bright gravy pools into an undulating bank of mashed potato, and a few token baby carrots lie about like battering rams. It is a very happy-making pie, a true pie, one of the great pies.

After that, an autumn fruit crumble (7) is raspberrily and quincily pink under a soft crumble topping, with a dear little jug of sweet, runny crme anglaise.

Service comes with many a flourish, but nothing is too much trouble. A blazered old boy wants tomato ketchup with his fish and chips yes, of course. Lady Dorinda wants a separate plate for her salad of dandelion and endive (3) yes again.

The wine list is full of honest, basic wines that work hard for the money, such as my 2004 Drouhin Bourgogne Rouge at 19.50, but those wishing for more glamour can choose a bottle from the Fortnum cellars for an extra 10 corkage charge, a generous gesture.

The Fountain has managed to retain all the good things about being old-fashioned, while subtly inserting a crisp, fresh, witty modernity for a new generation of diners. Busy for breakfast, frenetic for lunch and comfortably booked for the evening, it is currently the Christmassiest place in town. It feels not only restored, but restorative, with its excellent food, generous service and delicious new surroundings magicked from a fairy-tale exactly the sort of happy ending Dame Barbara Cartland would have written.

15/20

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

The Fountain, Fortnum & Mason, 181 Piccadilly, London W1, tel: 020 7734 8040. Breakfast and dinner Mon-Sat; lunch daily. Around 100 for two, plus service

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