Now this is what Soho is all about. An unmarked doorway on a side street. A dark stairwell leading up to a crepuscular first-floor dining room. Guttering candles casting pools of light in a shadowy room of shiny black and sexy red. Light slanting through Venetian blinds on to crisp white tablecloths. All the scene needs is a woman straddling a chair while unpeeling a stocking and we could be in a Jack Vettriano painting.

Maybe it could be called The Kissing Manageress. Sashaying towards me through the gloom comes a stylish woman with an incredible husky voice, like Campari poured over cracked ice. When I give her my name (or rather the name I've booked under) she leans in to greet me with a kiss on the cheek. I've never met her before, as far as I know. But this sultry little restaurant is the nearest thing you'll find in Soho to an underground dining club, and as soon as you cross the threshold, you're made to feel like a member.

Opened by Andy Campbell (ex-head chef of Zilli's) and his partner Alessandra, she of the sexy voice, the restaurant is on the first floor of a private members' club (though anyone can book a table). After a quiet opening in March, word has spread that here is a Soho restaurant of the old school; offering decent food in a raffish, bohemian setting.

The Friday-night clientele lived up to the billing: a little bit Fashion Week, a little bit rock'n'roll, though disappointingly transvestite-free (Wednesday is their night, apparently). Waiting for my friend in the semi-darkness, it didn't seem quite right to bring out the Evening Standard; ArtForum perhaps, or maybe just Forum. So I sipped a Negroni – brought up from the new HQ of cocktail king Dick Bradsell, two floors down – and people-watched. It all seemed charming to me, but my friend Sharon was unsettled by the tackiness of the pub-style carpeting and the weirdness of the atmosphere. "It's not weird, it's bohemian," I corrected her, as an enormous man with tattoos, jewellery and long blond hair loomed out of the darkness.

The menu changes daily, with a few classics – fillet steak and fries (£20) and classic Caesar salad (£6) – making repeat appearances, bolstered by appealing pan-European brasserie-style dishes such as mussels with white wine, confit chicken leg with dauphinoise potatoes, and gravadlax cured in Hendricks Gin. Most of what we tried was pretty good. A coleslaw-like salad of barrel-aged feta cheese, red cabbage, apple and walnut was better than it sounded, if reminiscent of something from a Marks & Spencer recipe book, circa 1981. Gruyère cheese and caramelised onion tart was properly crisp of pastry, and the accompanying salad leaves notably zippy (Campbell has created his own kitchen garden on the roof).

The DIY ethic extends to the charcuterie; we admired the home-made Jaegerwurst sausage, smoky and close-textured with a hint of fennel seed and other aromatic spicing, which came with proper, buttery mash and red onion gravy, plus a nose-clearing caraway beer mustard. My own main course of whole sea bass was, in retrospect, not something to be attempted in a nearly dark restaurant. My first attempt yielded a mouthful of tiny bones, and subsequent efforts left me feeling like I was flunking the skills test on Masterchef; I could almost hear Monica sucking her teeth and murmuring, "Chef won't be happy with that". Despite my efforts, the fish was really good, well-supported by a broth of clams and mussels, roasted potatoes and perfect green beans.

The brevity of the pudding list – just cheese and two desserts – reflects the limitations of the kitchen, which only has room for Campbell and a sous-chef. We ordered a chocolate Nemesis to share, and our wry, pony-tailed waiter, who looked like he might once have been on the alternative cabaret circuit, placed it between us saying, "I'll leave this in the middle and you can fight over it like the wild beasts that you really are".

Which really summed up the quality Andy's has in spades: personality. The front-of-house team, the other customers, the chef, who pops out regularly to commune with staff and greet customers; even the food, which like the best type of Soho character, is mildly eccentric, but designed for pleasure. With a couple of glasses of wine – well, we are wild beasts, after all – our bill totalled around £90, including service.

Ever since the 1950s, people have been telling each other that Soho isn't what it used to be. But really, the area is now a hellish scrum at weekends – the days when the Groucho Club didn't open on Saturday nights because the area was deserted are long gone. For the nostalgic Soho boho, or the merely curious, it's good to know that places like Andy's still exist.

As part of the London Restaurant Festival, Tracey MacLeod will tonight be taking part in Starter For Ten, a food-related quiz pitting restaurant critics against top chefs. Vinopolis, SE1, 6pm. See

Andy Campbell @ 23 Romilly Street 23 Romilly Street, London W1 (020-7734 9050)

Food 3 stars
Ambience 4 stars
Service 4 stars

Around £45 a head including wine and service. Set menu £12.50/£15.50 for two/three courses

Tipping policy: "Service charge is 12 per cent, of which 100 per cent goes to the staff; all tips go to the staff"