The involvement of celebrities in wine companies is becoming increasingly common. But while there may be marketing advantages in some cases, writes Philippa Jones, celebrity endorsement is no guarantee of success, and can distort a wine's price/quality ratio.

Until recently, the only link between Cliff Richard and wine was a Christmas hit single, Mistletoe and Wine. But the ageing British crooner has joined the growing list of celebrities who have decided to move into the wine business.

It is unclear whether most of them are committed oenophiles or whether they simply see the wine connection as a way to enhance their image and make a quick buck. But whatever the motivation, celebrity endorsement of wine appears to be a growing trend on both sides of the Atlantic, though quality continues to be more important to drinkers than even the most famous name.

The godfather of celebrity wines is - appropriately enough - US filmmaker Francis Ford Coppola, who began producing wine in the Napa Valley in the 1970s. He is well known as an oenophile and his wine generally receives rave reviews.

However, Richard Halstead, operations director at the London-based consultancy Wine Intelligence, warns that vineyards should be wary about who they choose to market their products, pointing out that certain names could have a negative effect on sales.

"The biggest challenge any wine faces is achieving a point of difference when there are 800 wines on the shelf from all around the world," said Halstead. "In this regard, having a celebrity endorsement is clearly going to set one wine apart. However, consumers can be suspicious of endorsed products, especially if the endorsement is not appropriate or convincing."

He agrees that "if it's Francis Ford Coppola making wine at his estate in Napa, that's fine", but suggests that if Wayne Rooney, the young English footballer known for his short temper and apparent lack of culture, lent his name to a wine, "it would probably put consumers off".

A couple of years ago the English actor Robert Hardy - recently seen as the Minister of Magic in the Harry Potter films - endorsed some of the wines already on the books of merchants Tanners Wines after writing an article for the company's magazine. "The case sold well as Robert is very well known, and the article caught the attention of our customers," says the group's marketing manager Alison Chadwick.

But Chadwick adds that in general the company does not stock wines endorsed by celebrities, primarily for financial reasons. "The main problem with a lot of celebrity wines is the cost," she says. "They tend to be expensive and although we don't claim to only sell cheap wines they do have to be great value for money - even if they cost GBP100 (US$206) a bottle.

"Our ethos is also to support smaller producers rather than mass-market wines that are generally sold in supermarkets," she adds. However, Chadwick says that "if a great value, great tasting wine made by a small producer who happened to be famous invited us to taste their wine I'm sure we would consider importing it".

First and foremost - "the wine is more important than the name on the bottle" - according to Chadwick, a sentiment shared by Ben and Georgie Furst who manage the Sussex Wine Company, also in the UK. They say it was the taste and price that had won them over to Francis Ford Coppola's wines, rather than the chance to market a famous name.

"We visited the vineyards and were impressed with the wine and the set up and when the product became available to the UK market, we decide to dabble with it," the Fursts tell just-drinks. "The wine is good and very realistically priced at around 60 pounds a bottle."

They admit that the Coppola name offers added marketing value, but point out that since the wine had been listed on their website around two months ago, they had the impression that "wine rather than film buffs" were purchasing the product. The Fursts have also been offered Cliff Richard's wine but, to say the least, have reservations about the wine's quality. "We do not think the wine is great," the Fursts state.

The Fursts say they are wary of celebrities cashing in on the wine trade to build their image or just because they have lots of money rather than getting involved because they want to produce good wine and manage beautiful estates.

Experts agree it is difficult to prove whether celebrity endorsement of wines work better in certain countries. Halstead suggests, perhaps unsurprisingly, that the positive, or negative, effect of this marketing tool depends on the profile of the celebrity in the country in question. "An icon in France - such as Gerard Depardieu, who makes wine in the Loire - will work in France, but perhaps not so much elsewhere," he says.

The US is still more celebrity-focused than Europe and therefore this trend is likely to be more successful on that side of the Atlantic, the Fursts believe. They also agree with Chadwick's view that celebrity-endorsed wine is often more expensive than wines of a similar quality and that this is another reason why the trend is more likely to succeed in the US as American consumers may be more prepared to pay that premium than Europeans.

Halstead is reluctant to forecast what the future holds for this market, however. "It is difficult to say what potential this market has," he admits. "A proliferation of celebrity wines would rather defeat the point-of-difference argument and undermine any momentum in the market. A well thought-through product with a good back story and some element of genuineness will always stand a good chance of succeeding, whether it's celebrity made or not."