Muriel sparks: In Glasgow, Tracey MacLeod is wary of being seduced by Nairns

It's quite an achievement for a chef to make regular appearances on Ready Steady Cook and still be thought of as cool. But Scottish superchef Nick Nairn has repeatedly supped with the daytime devil that is Fern Britton, without tarnishing his image as one of the few celebrity cooks you could bear to have a drink with. Nairn's gimmick is that he has no gimmick, though you could describe him as an Action Foodie. In his BBC series, Wild Harvest and Island Harvest, he bounds engagingly around Scotland, foraging for wild ingredients he then transforms into appetising meals, usually consumed on some mizzle-shrouded hillside.

Self-taught, Nairn built his reputation as the chef-proprietor of the Braeval Inn at Aberfoyle, where his fusion of Scottish tradition with modish treatments from Asia and the Middle East quickly won him a Michelin star. Last November, his empire expanded with the opening of Nairns in Glasgow, a smart townhouse restaurant/hotel which immediately became one of the city's most popular venues.

So I really should have known better than to have grandly promised the friend I was staying with a free lunch there, without bothering to check first that I could get a table. The place was fully booked, inevitably, and I had to admit defeat to my host, the broadcaster-turned-novelist, Muriel Gray. Only then did she quietly point out that she co-owns the company which produces Nick Nairn's TV programmes, and offer to make the reservation for me. Torn between Nolanesque probity and the desire for a good lunch, I let greed get the upper hand, resolving that I wouldn't allow my review to be swayed by the possibly partial attitude of my dining companion.

On a bright Sunday lunchtime, sunshine poured through the high windows of the elegant Georgian house that Nairns occupies in one of the West End's golden crescents. The interior has been gutted and redesigned with flair. Contemporary furniture and pale wood floors co-exist comfortably with original tiled fireplaces and dark wainscoting. The odd exuberant touch, such as a wall lined in gold leaf, betrays a sense of the theatrical at work.

Muriel's pal Isabel was waiting for us in the comfortable bar, lounging on a big squashy sofa and sipping a big squashy drink, while cool jazz tinkled in the background. I was wary she might be an accomplice in a Muriel plot to snare Nairns a favourable review, but her credentials as a local GP seemed unimpeachable. Under questioning, she was able to give a precise description of the frenulum, which was reassuring if not particularly appetising.

Nairns has two dining rooms, each containing around eight tables, and serving the same menu. The elegant pink room upstairs is slightly more formal, and would probably be the better choice for dinner. But we headed downstairs, to a sleekly contemporary basement in a minimalist palette of grey, white and black. A streaky paint effect gives a bare stone look to the walls, and the only decoration comes from some dramatic black-and- white foodie photographs by Calum Angus Mackay. But despite the monochrome colour scheme and the austere formality of the table settings, the room feels unchilly and welcoming.

The set-lunch menu, which changes daily, is concise, offering just three choices per course. This reflects Nairn's philosophy of sourcing the best local ingredients and delivering them at an affordable price (pounds 17 for three courses). I started with cauliflower and grain mustard soup, because Muriel assured me the soups are fabled for their lightness of touch, achieved largely without using a stock base. Foamy as a cappuccino and dusted with chives, it had a nutty delicacy of flavour, and was, as promised, light to the point of fluffiness (if soup can be fluffy).

Isabel's seared salmon, served with sauerkraut and thyme butter sauce, was deep pink in the middle, and vividly full-flavoured - obviously a local lad. "It's good. Very good," Isabel nodded gravely, employing her most serious bedside manner. Muriel had agonised about ordering the foie gras and chicken liver parfait, but having done so, said she found its creamy texture contrasted nicely with the robust accompanying fig marmalade.

So far, Nairns was providing a fine Sunday lunch experience. Happy family groups surrounded us, complete with snowy-haired grandmothers and gurgling babies. Service from a friendly young team of waiters was swift but relaxed, almost to the point of flirtatiousness. We could have been in Italy. "It's so un-poncey and unpretentious," as Muriel said, she whose intolerance of the poncey and the pretentious is the stuff of TV legend.

The only strike I could find against the place was the plates, each of which was tackily decorated with a florid signature from our eponymous host. In fact, as we later discovered, Nick wasn't cooking on the day of our visit (no doubt, he was out gutting mackerel or gralloching a deer), so it would really have been more appropriate for the sous-chef to have signed the plates. Or, at least, prefaced his boss's signature with a "pp".

My second gripe came with the arrival of my main course - two very small and decidedly dry squares of pan-fried John Dory, accompanied by candied yams and rather anaemic puy lentils. "So this is how he keeps his prices down!" I crowed at Muriel, waving one of the child-size portions under her nose.

By way of reply, she nodded to her own tower of char-grilled lamb chump, which she had to handle carefully for fear it might topple like a Fred Dibnah chimney. As she excavated her way down, through the layers of red onion, spinach and tender lamb, she cried: "It's like Tomb Raider! I am Lara Croft!" But even she had to admit the onion Rosti and the caramelised shallots were oversalted.

Also marred by too heavy a hand on the salt pot was Isabel's aubergine and plum tomato pizza, which again came in a size more appropriate for a starter. She enjoyed it, though, and dug down through the topping to see if Nick Nairn might have signed his autograph in capers on the crust.

I had plenty of room left for pudding, so went for the greediest option - a steamed chocolate sponge. This was pleasingly light in texture, but dark in taste. Isabel's lemon parfait was positively ascetic by comparison, a demure pyramid in a pool of toffee-ish sauce, which she pronounced satisfyingly creamy and tart. Muriel continued her Lara Croft act on a baked apple, diving into the dark brown crusty sphere to retrieve sultanas, dried fruit and walnuts from its slippery recesses.

Unconsciously, we had adopted a spread-betting approach when ordering, and we realised that between the three of us, we'd managed to eat everything on that day's menu. "Let's start working our way through the wine list now," Isabel suggested, proving she's one of those GPs who stands very much on the "two glasses-a-day-and-over" side of the health debate. Our bill for three came to around pounds 90, including a bottle of Gewurtztraminer from a short and reasonably priced selection.

"That was one of the nicest restaurants I've been in," I said as we left, "but, you know, I have to make sure it doesn't just look like a plug for your TV series." "Oh, never mind about the TV series," Muriel replied, "how about a mention for my new book?" Nairns, 13 Woodside Crescent, Glasgow (0141 353 0707). Lunch, 12 noon-2.30pm; dinner, 6pm-10pm. Closed Monday. Lunch, pounds 13.50/pounds 17. Sunday lunch, pounds 18.50. Dinner, pounds 23.50. Accommodation: pounds 90-pounds 120 (room only). All credit cards except Diners. Limited disabled access.