Forget the chardonnay. Champagne is now such a bargain that you can afford to enrich your TV dinner with the fizzing nectar. But will we want to open champagne at christenings, seduce with it, or use it to show off our affluence when it has become quite non-exclusively cheap?

Forget the chardonnay. Champagne is now such a bargain that you can afford to enrich your TV dinner with the fizzing nectar. But will we want to open champagne at christenings, seduce with it, or use it to show off our affluence when it has become quite non-exclusively cheap?

The bargain prices are the fault of makers who thought they could benefit from high millennium demand, miscalculated and were left with a glut. And where there's a glut there's a price war.

Like much French regional produce, champagne holds an appellation contrôlée, no similar drink can be made outside the area and give itself the same name. An appellation contrôlée gives a brand an air of exclusivity.

One imagines a mere handful of pampered, black-legged poulet de Bresse are available to those willing to pay £15 a kilo. Roquefort, maturing in its caves, is made in minute quantities which the price reflects. But when a so-called exclusive label reveals its ability to reproduce on a grand scale, to the point that it finds its image plastered against supermarket windowpanes ­ "baked beans 12p! Duval Leroy £6.99!" ­ it's risking an imminent loss of cachet.

The fashion industry plays Russian roulette with its designer labels. If they are worn by the few the many will hanker after them. But once the many have bought the T-shirt, the influential few will look elsewhere for something to patronise. "Look at Prada," a fashion editor says, "there is so much Prada, it has saturated the market and become too accessible." Then, dismissive sotto voce, "Everyone's wearing it."

Yep, it's everywhere all right, on every shoe, bag and zipper. And with a loss of exclusivity, often comes the suspicion that there may be a loss of quality. The makers will protest, but there are grounds for that unease.

Salmon was a rich man's fish until modern aquaculture made it possible to produce ton upon ton of it in fish farms. The price went down, and the shoppers' perception was that the quality was as high as that of its wild cousin. Now it has been revealed that intensive salmon farming raises serious health and environmental concerns, and farmed salmon has lost any cachet it once had.

It is not only the salmon whose fortune has been reversed. The biddable cod, so easy to catch, has been chronically overfished. Atlantic stocks are low and a 10-week fishing ban has been enforced in the North Sea, due to be lifted next week. The staple of a cheap fish 'n' chip meal is now soaring in price and allure in starred restaurants.

In Perugia, Umbria, home to Italy's favourite fungi, the white truffle, millions have been invested in a scheme to impregnate the roots of oak-tree saplings with the spores of truffles. Success could mean truffles will be sold alongside potatoes and other mass-produced foodstuffs. Meanwhile, Cornwall has applied for its own appellation contrôlée, for the pasty. Will you foot the bill for a limited-edition, native pasty? I guess you will.