Green and Black's Maya Gold chocolate, named after the Indian farmers who harvest the cacao beans, will be on sale in 80 Sainsbury stores from Friday. It is the first product to carry the Fairtrade Mark, signifying approval by Oxfam, Christian Aid, Cafod and the World Development Movement.
The Fairtrade Foundation, which also includes consumer groups and the National Federation of Women's Institutes, vets products to ensure their producers receive a reasonable price and guaranteed contracts. Workers' rights and health and safety are also safeguarded.
In the village of San Jose in Belize, farmers were forced to abandon their trees when the price of cacao fell by more than 50 per cent to 22p a pound. However, the deal with Green and Black's, signed last November, pays them 48p a pound and involves a three-year guarantee to buy all they can produce.
Jo Fairley, a partner in the family firm, which makes organic chocolate approved by the Soil Association, said she and her husband met the farmers when they visited Mayan relics. 'We were offered some of their kukuh drink and we realised they were growing it organically.
'The Maya have been really let down by big companies who come along and offer them a very high price but with absolutely no intention of ever fulfilling it,' she said.
According to a recent poll, more than two-thirds of shoppers are prepared to pay more - up to 32p on a product costing pounds 2 - for goods if they are sure Third World producers receive a fair return.
The Maya Gold brand will cost pounds 1.55 in Sainsbury's for 100g, compared with 65p for the same amount of Bournville.