Cadbury is to set to secure Fairtrade status on millions of Dairy Milk bars in a new landmark for the ethical badge.

The move, which also includes its packaged cocoa, makes Cadbury the largest mainstream confectioner to adopt the certification and comes with sales of Fairtrade products booming despite the economic downturn.

Fairtrade sales have risen by 40% in the past year to more than £700m, according to new figures from the Fairtrade Foundation.

“If there are only small players in Fairtrade, it’s sort of self-defeating,” said Cadbury chief executive Todd Stitzer. “If big businesses get behind it, you can have a much greater impact on agricultural societies.”

Fairtrade Foundation chief executive Harriet Lamb, who last week called on retailers to put the ethical certification at the heart of their policies, said Cadbury’s move was set to “throw down the gauntlet” to rival confectioners and other major manufacturers.

“It’s an iconic British brand,” she commented. “This does really set the pace for the mainstream industry.”