People have the power

Boycotting things with which - or people with whom - you do not agree can have a dramatic effect. The seventies boycott of trade and sporting links with the apartheid regime in South Africa worked. On the same principle, I won't be recommending Chinese wine - because of Tibet - or writing about those from Israel.

But can you carry it too far? Should I extend this disavowal to Californian and English wine because of the American and British invasion of Iraq? Should I have banned French wine from my Guardian column, as a number of readers insisted I should, when that country carried out nuclear weapons testing in 1996?

And, today, should we boycott Tesco? The retailer has left an extremely nasty taste in the mouth over its wholly disproportionate hounding of critics of its expansion plans in Thailand. I am seriously considering forgetting to attend the next Tesco wine tasting. Although I am no longer a member, I urge all members of the Circle of Wine Writers to consider doing likewise.

If I still published my Superplonk book I'd be happy to chuck Tesco out unless they do the decent thing and stop its Thai subsidiary from pursuing libel claims which run, in one case, to an obscene 16-million.

Malcolm Gluck is the wine critic of The Oldie magazine

• Harpers Says...