Historically, there have been tenuous links between farmers and food producers, with many companies having scant knowledge of how and where their ingredients are grown. But as the prices of raw materials soar - from the barley used to make beer or the cocoa used to make chocolate - leading brewers and food manufacturers from Cadbury Schweppes to Diageo are increasingly recognising their businesses will benefit from investment in agriculture.

Andy Redfern, co-founder of the website Ethical Superstore.com, has no illusions about consumers who claim to be green. "We had a rush last year on solar iPod charges . . . and most of them were going to Glastonbury," he says. Even if people who buy things with an environmentally friendly claim do so for selfish purposes, there is no doubt that people are buying more of them.