Consumers were urged yesterday to avoid buying any bottle of wine costing less than £5 because it would almost always be "inferior".

Consumers were urged yesterday to avoid buying any bottle of wine costing less than £5 because it would almost always be "inferior".

The Consumers' Association claimed that, at the bottom end of the range, customers pay largely for bottling, tax and marketing and "corners were being cut" on basic ingredients.

In the Which? Wine Guide 2005, the authors said supermarkets were putting pressure on growers to accept sub-standard grapes and were threatening the diversity of the fruit.

Susan Keevil, editor of the guide, said: "Wine priced below £5 encourages a grower to accept yet another batch of substandard fruit, which in turn leads supermarkets to stifle yet another quality check or stamp a quirky grape blend out of existence. This price point is becoming more difficult for growers to hit, yet supermarkets put pressure on them to meet these targets. For the consumer, buying at this price point can only mean inferior-quality wine."

It is claimed one supermarket asked suppliers to take a 1.25 per cent cut in 2004. "Even making bulk quantities of wine will incur costs and, for every penny that the big muscle-buyers want to save, a corner must be cut somewhere. The resulting wine will taste worse."

Tesco said it was "shocked" and said suggestions that low prices meant low quality were "snobbish". A spokesman said: "We make no apology for helping to bring down the price of wine so more people can afford to enjoy it and we would never do this at the expense of quality. It is too simplistic to assume that just because a wine is affordable it is not good quality."

The guide recommends big-name brands such as Piat d'Or, Blossom Hill, Banrock Station or Kumala over supermarket own labels at a similar price. These wines are usually blended from a variety of regions to a specific flavour formula.

John McLaren, of Wines of California, said the brands were more dependable. He said: "The styles are becoming much more UK-orientated. Gallo Turning Leaf is far less sweet than it was and the wine is attuned to the British palate. For own-labels, buyers are much more pragmatic; they'll buy whichever one is the cheapest for their generic chardonnay or merlot - and that often means sweeter local styles." The guide claims that some of the big-brand wines such as Oxford Landing and Jacob's Creek are refusing to accept supermarket price reductions and are investing money in their wines.