Fifteen, London

Jamie Oliver's new venture scores big, combining great food with a worthy cause. If only he could keep the neighbours sweet, says Tracey MacLeod

You've probably seen the series. You may even have bought the accompanying book. I'm sure I needn't explain the story behind Jamie Oliver's restaurant, Fifteen, staffed by dole queue kids turned professional chefs (not to mention reality TV stars). Jamie is emerging so well from the series – patient, passionate and inspiring – that it's almost possible to forgive him his posing, pukka-ing past. In fact the project is so patently worthwhile, it would be hard to find anyone who could possibly object to it.

Well I've managed to find that person. My friend Clare owns the flat above Fifteen, (only this being Hoxton, it's a loft) and has spent the last year locked in conflict with Oliver's army. It was Clare who delayed the opening of Fifteen by objecting to the original positioning of the ventilation flue (to his credit, Oliver tore up the plans when she tearfully put her case). She's currently glued to the series, alert for fresh outrages, like the revelation that Jamie is planning to open an all-night bakery, and had stormed down that morning to protest about the constant low hum from the flue.

Who better, then, to give Fifteen an objective review? "This is the first time I've been down here not to complain," she marvelled as we took our places in the futuristic basement restaurant. There's a less formal bar upstairs, filled with young Hoxtonites; downstairs the look is Clockwork Orange meets space lounge, all extruded white plastic and recessed padded cells (in case one of the trainees punches a wall?). Groovy ovoid serving hatches allow glimpses of the trainees at work alongside Jamie and his crew. Only the previous night, we'd watched them flunking their exams, so it felt a bit like fast-forwarding to the triumphant final scene of the series.

The manager rocked back on his heels when he recognised his very own Neighbours From Hell, in the form of Clare and her girlfriend Alison, but swiftly recovered to offer a round of aperitifs on the house. "Free Bellinis for the Nimby lesbians," snorted Clare. The arrival of the bread basket almost triggered another outburst about the all-night bakery, but the bread, including tomato, walnut and focaccia, was so good it seemed to calm her down.

Fifteen's daily-changing menu is written in Jamiese – (scallop crudo is "kinda sashimi") but its enthusiastic adjectives – "good oil", "melt-in-the-mouth oxtail", "fantastic wild mushrooms" – are winning rather than annoying. Just as his books are full of must-cook dishes, this is a must-order menu. It's kinda expensive; main courses are priced at £18-£20, but as Clare cynically pointed out, unemployed trainees don't come cheap.

At first bite, however, cynicism turned to rapture; each of our starters was glorious. A Middle-Eastern-influenced combination of jewel-like pomegranate seeds, raw scallops, herb shoots and coconut in a sour lemon dressing was that rare thing, a genuinely new taste sensation. Its recipient, objectivity rapidly melting away, declared it "the most wonderful thing I've ever eaten in my life". Nearly as radical was an assembly of fresh tarragon, grapes and goat's cheese, billed on the menu as "my new favourite salad". Both our pastas – pappardelle with slow-cooked rabbit, and oxtail ravioli in a gloriously rich broth – compared favourably with equivalent dishes recently sampled in The Connaught and Locanda Locatelli.

There's an exciting "as seen on television" aspect to some of the main courses. We'd watched the trainees visiting Peter Gott's Cumbrian farm the night before, so knew that the tastiest bit of the pot-roasted pork loin would be the fat, kept moist by prosciutto wrapping, and so it proved. We'd also slavered over Jamie's beef fillets poached in red wine, and here was one in the flesh, meltingly soft, and rather more elaborately dressed than the prototype, with wild mushrooms and a riot of chopped herbs joining the creamy mashed celeriac. Sea-bass (line-caught, natch) was lightly breaded and pan-fried with crunchy battered artichokes, while a plump little roast partridge was partnered with creamy nutmeg-scented polenta.

Puds are less interesting but perfectly competent; the best we tried was a faintly lemony panna cotta partnered with spicy poached berries. The only thing Clare could find to complain about was the pricing of the wine list; the mark-ups are stupendous, and there isn't much choice below £30.

We stayed at the lower end of the wine list, but still our bill came to £50 a head; for food of this quality, though, it seemed appropriate. Jamie Oliver's pulling power ensures that the diners are a lot more mixed than you'd normally get in trendy Hoxton; nervous young couples and families celebrating special occasions had their evenings made even more special when their copies of Jamie's Kitchen emerged from Jamie's kitchen, duly signed.

As a restaurant, it's mouth-watering; as a project, heart-warming. Before we left we chatted with Nicola and Kerry-Ann, two of the series' more prominent slackers, who quizzed us proudly about what we'd eaten, and for the second time that day, Clare left the restaurant feeling a bit emotional. "I never thought it would be as good as this," she said. "He's a genius. But he's still got to do something about the noise from that flue."

Fifteen, 15 Westland Place, London N1 (020-7251 1515)