Not long ago, a diner at a London restaurant sent back a magnum of 1961 Château Pétrus costing £18,000 ($29,661). It was fake, he said. That's the kind of person I want to eat with - one who can afford to spend that much on wine! Then know it was counterfeit.

Professor Günter Schamel of the Free University of Bolzano revealed to this year's recent meeting of the American Association of Wine Economics his studies into 260 eBay auctions of empty wine bottles. Why, he asked, would anyone pay over 100 euros for an empty bottle of 1982 Chateau Lafite-Rothschild unless they were going to fill it up again for re-sale with inferior wine?

But apparently, those who buy prestige bottles at well below that staggering price may also be duped. They're in danger of being sold modest wine poured from high-end label bottles that have been bought second-hand off eBay.

Even at the cheaper end of the market, you can be taken for a ride. Inform yourself - and find some really good bargains - with a copy of The Wine Trials.