Global sales of Fairtrade goods  grew by more than a third last year to £758m as increasing numbers of big name retailers got behind the scheme, as well as more specialist retailers such as the Ethical Superstore , according to new figures.
Sales of Fairtrade coffee , perhaps the most established product, continued to grow strongly during 2005 and other more recently certified goods including flowers and textiles made substantial gains.
Britain is the biggest market for Fairtrade goods in volume terms.
According to figures from the Fairtrade Foundation , sales in Britain reached £195m in 2005, a 40% rise on the year before. The Fairtrade Foundation is the UK member of the Fairtrade Labelling Organisation (FLO), which administers the worldwide scheme. "Retailers are switching over to Fairtrade goods because of consumer demand," said Barbara Crowther, a spokeswoman for the foundation.
She said the foundation had often posed the question about what motivated retailers to get involved and whether there might be room for cynicism. "The producers view is that they don't mind why the retailers are doing it, as long as they do and they do it properly," she said.
"The onus is on us as consumers to keep driving the demand so that businesses think it's the right thing to do for their businesses as well as part of a wider corporate social responsibility."
One of the biggest converts in Britain this year has been Marks & Spencer, which in March switched its entire range of coffee to Fairtrade producers. The company is now working to switch its tea to Fairtrade producers and is introducing Fairtrade cotton across its clothing range.
Farmers in Mali and Senegal are providing Fairtrade cotton for M&S jeans and underwear, and farmers in Gujurat, India, are producing certified cotton for T-shirts and socks. At the recent M&S results, the chief executive, Stuart Rose, said: "Our customers have told us they care about how our products are made."
The Fairtrade label appears on products as a guarantee that producers get a certain price for their goods that at least covers the cost of production and is usually better than the market might offer. In recent years the price of coffee has fallen as low as 45 cents a pound (55p a kilo) on the open market - farmers in the Fairtrade scheme are paid .26.
Producers also get a premium that is put into social, economic and environmental projects, including schools and health centres. To be certified, the producers need to meet certain standards on labour and the environment.
The FLO said the number of retailers offering certified goods had grown last year by 300 to 1,483. There are now 508 certified producer groups in 58 countries.
Tesco sells Fairtrade goods including teabags, oranges, herbs and spices. A spokesman congratulated the FLO and said: "We look forward to working with them ever more closely in the future."
Ms Crowther said retailers were getting involved in different ways. The Slug and Lettuce pub chain began selling Fairtrade coffee  after being encouraged by a customer, giving it a try locally and then rolling it out nationally. "Of course, there is an awful lot further we can go," she said.
An Oxfam spokeswoman said that growth in Fairtrade goods has been "phenomenal" in the past decade. "It has become an everyday thing, which we would never have imagined 10 years ago."