"I should have been Italian," announces Jamie Oliver at the start of the on-line 'mission statement' for his bustling and appealing new Oxford restaurant, Jamie's Italian. His many fans can only feel relief, however, that his nativity was destined to be elsewhere; Britain's most famous Essex-boy would otherwise have been denied his fame and fortune, and his place in the nation's heart. Or would he? Perhaps he might have spent his youth in Italy before shaking off the soil of his homeland to make it big here in the manner, say, of Antonio Carluccio with whose hugely successful British operation Jamie's new venture will inevitably be compared - not entirely to its discredit.

True, certain sniggering summer visitors to Chiantishire might study the menu at Jamie's Italian and wonder what is especially Italian about "organic Shetland salmon", "grilled Welsh lamb chops", "fantastic British beef" and "lovely free-range chicken from the West Country". These smart alecs should be told - politely or otherwise - that Jamie deserves praise for sourcing his ingredients so impeccably. It is, furthermore, more important, in terms of a claimed Italian pedigree, how raw materials are used - rather imaginatively, as it turns out - than where they originate.

Jamie's Italian occupies substantial premises - ground floor and basement - on the corner of Gloucester Street and George Street (already, of course, well supplied with ersatz Italian establishments). I remember the building only as the home of Young's never-much-good Cock and Camel pub and before that the (rather useful) Rollers discount store. During the recent renovation, however, passers-by were reminded of its earlier function as the clothing department of the Oxford Co-op, with the uncovering of brass-trimmed window panels advertising "boys' wear", "sportswear" and the like.

That these were preserved during the revamp - and remain on view - is a tasteful touch I think worthy of commendation. So, too, does the director of the Oxford Preservation Trust, Debbie Dance, whose opinion I canvassed during the 45 minutes Rosemarie and I spent as members of the same queue waiting on the pavement for our first taste of Jamie's Italian.

Regular readers might be surprised to find me queuing for anything. I confess I was slightly surprised with myself. But this is a restaurant where you can't book (except for a party of eight or more). As a means of giving the severest test to the operation, I chose to visit at the busiest time - 8.30pm on Saturday night - in the first week of opening. That we were satisfactorily seated in an hour seemed perfectly acceptable in the circumstances.

My seat in the rear section of the basement, as I learned from a member of the staff, had been occupied a few days earlier by the great man himself during a training session attended by many of his friends - 'mates' as these would surely have been styled. Il padrone was referred to as "Mr Oliver", though I feel sure this was misdirected deference from the waiter rather than any insistence on forelock-tugging by his man-of-the-people boss. And what had Jamie eaten? A burger or, to give it its full monicker, " a char-grilled chop steak organic buffalo burger".

My meal was rather more obviously Italian, beginning with huge green Nocellara olives, served on ice with a side dish of black olive tapenade and "snappy music bread" - Jamie's name for crispy Sardinian carta di musica. The pieces here were not actually very crispy, alas, and neither were those in the bread basket which also included excellent sour dough country bread and focaccia, and grissini.

I continued with a first-class plate of truffle tagliatelle, the pasta both slippery and al dente with a buttery sauce flavoured with parmesan and nutmeg. The thin shavings of wild black truffle were plentifully supplied, despite the cost of this delicacy. Generous, too, was the juicy chunk of baked organic salmon that formed my main course; the crisp-skinned fish was nicely teamed with the aniseed flavour of the chopped fennel that accompanied it, along with red onion, tomatoes, basil, lemon and olive oil.

Curiosity rather than hunger led me to order a number of side dishes. The bean salad with herb shoots and slow-cooked balsamic chickpeas were both highly rated, but the "flash-cooked" greens were so tough that even a cow, with its cud-chewing ability, might have found them hard to swallow.

Rosemarie's starter was a "meat anti-pasti plank", a real bargain at £6.50 since the long wooden plate contained bresaola, fennel salami, pistachio mortadella and prosciutto, as well as cheeses with chilli jam, green chillies, mixed olives and salad. The plank was placed, rather absurdly, on a base of tomato tins. I fancy this method of serving will not survive long, as Jamie expands the new restaurant chain to Bath, Chester and elsewhere.

The char-grilled catherine wheel pork sausage of her main course was fine (if rather salty) but the "ouzey" (oozy?) parmesan and mushroom polenta beneath was better described, she said, by the adjective 'claggy'.

Rosemarie seems to be less fortunate than I at Jamie's Italian. When we returned last Sunday (no queue this time), her spaghetti bolognese was marred by undercooked pasta, though the classic ragu (beef, pork herbs, wine and parmesan) was as it should have been. I had "Jamie's flash steak" - the meat pounded thin, flash griddled and served with a spicy salsa.

At the Saturday dinner, I had passed on pud. Rosemarie enjoyed the oddly named "Italian Bakewell tart", with Derbyshire's classic almond and jam cake teamed with lemon and orange crème frâiche.

Pukka, as somebody once said.