The UK’s best-selling chocolate bar has become Fairtrade certified, increasing the amount of Fairtrade cocoa sourced from West Africa.

Cadbury’s Dairy Milk has made the move – tripling the amount of Fairtrade cocoa sourced from Ghana to about 15,000 tonnes a year – in the summer.

The total annual cocoa production of Ghana is more than 600,000 tonnes.

The Fairtrade mark is designed to secure a better deal for commodity producers in developing countries.

Under the Fairtrade scheme, Cadbury will pay a guaranteed minimum price, even if the open market price falls below it, for Ghanaian cocoa.

However, although the open market price for cocoa has slipped in recent weeks, it still stands above the level guaranteed by the Fairtrade commitment.

The move is part of the Cadbury Cocoa Partnership, a £45m initiative over 10 years designed to help cocoa farming communities across the developing world.