Inn the Park, London SW1

There is a man walking his ferret in St James's Park. A guide dog is released from his harness and goes off to sniff the flowers, keeping a wary eye on his charge. A very small red duck indulges in a rather embarrassing mating ritual with a magnificent, and much larger, brown duck. Not a chance, mate.

There is a man walking his ferret in St James's Park. A guide dog is released from his harness and goes off to sniff the flowers, keeping a wary eye on his charge. A very small red duck indulges in a rather embarrassing mating ritual with a magnificent, and much larger, brown duck. Not a chance, mate.

But strangest of all is the apparition of a pregnant stretch of turf, rising in a fecund curve of spring green from the earth. On one side, its belly is slashed open to reveal a broad sweep of café, verandahed in birch, with a wall of glass facing greenery, ponds, and mating ducks.

Exterior, Sir Michael Hopkins. Interior, Tom Dixon. Food, Oliver Peyton. But I refuse to be seduced. London's past record in municipal catering is such that if you are eating something good in a park, garden or public space, you probably brought it with you.

Peyton (pedigree: Coast, Mash, Somerset House, Isola, The Atlantic) reckons he can change all that. He has set himself an ambitious task to be all things to all park-goers. At Inn the Park, there is inside and outside table dining all day, as well as take-away drinks, cakes, sandwiches and salads from the long take-away bar.

The striking interior works better by day than by night, when it feels more like a collection of conversation pieces that a coherent, fluid design. Talking points include mirrored flying-saucer light fittings, tubular-steel chairs with mock-croc leather upholstery, tables topped with high-gloss enamel, and a dining area shielded from the potential vulgarity of the take-away counter by several stable boxes of white marble.

To implement his dream of providing public catering of restaurant quality, Peyton has combined the talents of Isola chef Mark Broadbent, Mash chef Simon Wadham and former L'Oranger chef Kamel Benamar, all of whom take turns in the kitchen while training the kitchen brigade.

What makes it special is the dedication to all things British. So there is traditional lemonade and ginger beer and - hurrah, shout Julian, Anne, George, Dick and Timmy - no Coca-Cola. Not even filtered Thames water. For breakfast, you can order boiled egg and soldiers but no croissants. At lunch, there might be dressed crab or roast pork with scrumpy sauce, while dinner could be Welsh smoked salmon and cucumber pickle or fish and chips. Sweet things return to Famous Five territory, with strawberries and clotted cream ice-cream and Bakewell tarts. There is even an English sparkling wine on the something-from-everywhere wine list.

The current menu seems a little disjointed and trans-seasonal, with half a dozen rock oysters listed as a main course, and a tendency to be too meaty and macho for its springlike environment. A watercress salad with beetroot, warm poached egg and "crisp" Denhay bacon (£6) is flat and dull, the bacon anything but crisp. Prawn cocktail "Marie Rose" (£7.50) is neither reinvented nor deconstructed, remaining the gloopy, rich, lettuce and pink cream cocktail it has always been. Next, a grilled British Lop-Eared pork chop with a terrific apple sauce (£9) sits on a squidgy pancake of bubble and squeak.

But a roast leg of South Downs lamb (£13) is a joy, the meat rare and rested, with a light and lovely jus and perfect green beans. A side dish of buttered spring cabbage (£2.50), brightly green and subtly perfumed with mint, lifts a humble vegetable into the premier league.

The real strength of Inn the Park, however, is Out the Back, where pastry chef Jane Huffer, formerly of The Square, has the ability and the grace to turn out dazzlingly simple ice-creams, rustic tarts and sticky Yorkshire tea buns with the same angelically light hand.

Tonight, a wedge of rustic, scorchy plum and almond tart (£4.50) tastes freshly baked, served with a deliciously cold custard. Scones, not on the dinner menu but kindly put together for the scone fanatic at my table, are light and fresh, served with clotted cream so rich it feels caramelised. Tea is loose-leaf and comes in a very Noddy and Big Ears teapot that confirms my belief in Enid Blyton as one of the great unacknowledged design inspirations of the century.

There are things not to like: the off-putting smell of frying whenever an order for pollack and chips is fulfilled, and junior floor staff who run amok like headless chooks. But there are too many things to like: the thought of sitting outside in the summer months with a cool salad and a glass of wine, the promise of picnic baskets to take to your hired deck chair, after-work cocktails at dusk on the terrace.

In the past 10 years, London has made a name for itself for its high-end dining, at the tip of the pyramid. Now it is time for that quality to spread down to a lower price-point and a wider audience. It is too late for Britain to have a food culture built from the ground up, so we can only hope to do it from the top down.

Bringing good food to the people is never going to be a walk in the park, so the sooner Inn the Park settles in, smoothes itself out and succeeds, the better, for the future of all walks in all parks.

14 Inn the Park St James's Park, London SW1, tel: 020 7451 9999. Open daily for breakfast, lunch, tea, dinner, and sandwiches and cakes to go. Dinner, about £70 for two with wine and service

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

Second helpings: More food in wide-open spaces

Lake Country House Llangammarch Wells, Powys, tel: 01591 620 202 This imposing, immaculately presented Welsh country house sits in its own 50 acres of parkland, complete with riverside walks and sweeping lawns. In the atmospheric dining-room you can enjoy Modern Celtic cuisine, which apparently means caramelised scallops with creamed leeks, stuffed saddle of rabbit with lentils and honey and cider-glazed Gressingham duck.

Lochgreen House Monktonhill Road, Southwood, Troon, Ayrshire, tel: 01292 313 343 Owned by the unfortunately named Costley Hotel Group, this grand Edwardian mansion is all class. Set among 30 acres of woodland adjacent to the fairways of Royal Troon, the place is a magnet for golf lovers. Food-lovers are drawn here too, thanks to the refined cooking of Andrew Costley and his warm monkfish salad with foie gras, and roast gigot of Ayrshire lamb.

The Belvedere Holland Park Gardens, off Abbotsbury Road, London W8, tel: 020 7602 1238 My favourite London park is blessed with a romantic and intelligent restaurant. Located in what was once the Summer ballroom to Holland House, complete with vaulted ceilings, intricate parquetry floors and a small but lustworthy terrace, the Belvedere offers amiable set-price menus of typically Marco Pierre White fare (parfait of foie gras, salmon confit, rib of Aberdeen Angus).

E-mail Terry Durack about where you've eaten lately at t.durack@independent.co.uk