If there is one thing that links the myriad constituencies that form this country, that thing is the glib belief that every last one of us could run a restaurant. Even those few souls as yet unpersuaded that they could write a novel to make Nabokov look like Archer, and the even tinier minority who suspect that they might not be up to running the country, are sure of this. Well, it looks so easy, doesn't it? And such fun, too.

Should you be among the 99.93% of British residents who share this conviction, and are therefore currently contemplating putting your money in the vicinity of your mouth by actually opening a restaurant of your own, allow me to offer an antidote before it's too late. Take a lunchtime stroll along the Goldhawk Road in west London, erstwhile home of Steptoe & Son, and glance through the window of this little Polish place I know. On an unusually busy day, you will see one or two people eating there.

When I say that Patio would undoubtedly be one of my Desert Island Diners, the scale of the challenge here becomes apparent. There is little that its owner, Ewa Michalik, could do to improve her restaurant, yet after some 20 years of serving colossal quantities of good, solid Polish food with limitless warmth and patience, not to mention at dementedly low prices, she still cannot fill the place.

Admittedly, the hideous, greeny-yellow frontage is a deterrent to even the most undiscerning of passersby, while a pernicious local council has, for long chunks of the day, made parking within walking distance of the restaurant just about impossible without a resident's permit. Meanwhile, traditional Polish cuisine is hardly to all tastes in an age when goose fat features on the advice sheets of so few leading dieticians. For all that, the walls inside Patio scream under the weight of eulogistic reviews from the likes of Fay Maschler, Michael Winner and my predecessor on these pages, Matthew Fort - and no wonder, because Patio is a truly magnificent restaurant.

In some ways, it feels less like a restaurant than the living room of an educated friend in 50s Warsaw - beaten-up old piano, lumpen furniture, samovars, mirrors, bowls full of fruit and fresh flowers - where you are politely requested to make a token contribution towards the cost of your meal. Presumably some sort of profit margin must be built into Patio's pricing of food and drink, but I have never quite worked out where.

I have taken dozens of people to Patio over many years, and every single one of them has been utterly bamboozled as to how they could possibly be served such a meal - a huge portion of good, pale smoked salmon with blinis, for example, followed by a vast chunk of venison, beef or rabbit, followed by a Goliathan slice of cake, followed by fresh fruit, coffee, chocolates and a shot of vodka - for such a ridiculous all-in price (currently £15.99). Where other restaurateurs would claw something back via the familiar trick of tripling the trade price of their wines and flavoured vodkas, Ewa Michalik persists in charging little more than you'd pay for the same in the local branch of Majestic.

Even if the food were average, this would be a cracking venue for a lively, vodka-charged meal, but the dishes on offer at Patio are no more that than they are elegant, dainty or a close friend of the coronary arteries. The pick of the starters are the (off-menu) kabanos sausages, served aflame with beetroot horseradish and pickled cucumbers; and the red borscht, a soup studded with meat-filled ravioli and of such intense, lustrous flavour that the saliva glands go berserk at the very memory. Any of the main courses, which come with a bewildering array of vegetables including potatoes roasted in goose fat, would sate a small army of tapeworm sufferers, the highlights including golabki (stuffed cabbage), pierogi (meat-, mushroom- and cheese-filled dumplings), salt beef, chicken walewska (a plump fillet covered in peppers) and calf's liver for which even my mother, a terrifying stickler in such matters, has never had a harsh word. For pudding, the rum-heavy sweet-cheese pancakes are exemplary and the baked cheesecake divine.

Over the years I have many times tried to cajole Ewa, a trained pharmacologist, and her concert musician husband Kaz, who both fled Poland during the unlovely era of Jaruzelski, into being more realistic with their pricing, not least because the corollary of that old "reassuringly expensive" Stella Artois tag-line is, of course, "off-puttingly cheap".

They won't have it, though, partly through a sense of duty to their core clientele in this resolutely ungentrifiable part of London, and this despite overheads going through the roof. Such is the price of running a business as a labour of love.

Whether the reciprocal adoration felt by Patio's regulars makes it all worthwhile, I cannot say. But every time I walk down Goldhawk Road and see this uniquely wonderful little place once again unfilled by paying customers, I am reminded that, while I may yet emulate Winston Churchill by becoming both prime minister and Nobel Laureate for literature, the one thing I will never do is try to run a restaurant.

Patio: 9/10

Telephone: 020 8743 5194
Address: 5 Goldhawk Road, London W12
Open: Lunch, Mon-Fri, noon-3pm' dinner, all week, 6-11.30pm