The executive director of the Fairtrade Foundation has said there are no plans to extend the scheme to hard-hit UK dairy farmers.

Harriet Lamb was forced to defend Fairtrade's policy of not including farmers in developed markets in its certification during the British Business Embassy's food, drink and retail summit. The summit took place as UK dairy farmers continued to protest against low farmgate milk prices paid by retailers and processors.

"We've looked long and hard about whether we should use Fairtrade in the rich world," Lamb told the international audience. However, she said Fairtrade certification for developed world farmers is not likely any time soon.

"Standards would have to be changed so much, they'd be unrecognisable," said Lamb. "Secondly, consumers associate Fairtrade with developing world problems. I'm not saying dairy farmers' problems aren't serious, but we're talking about basic things, like lack of schools."

She also referenced one developing world farmer, who "banged his fists on the table and told me 'the day that Europe and the US get rid of unfair tariff barriers on agriculture, that's the day when you can do Fairtrade'".

Lamb added: "It's not never, but we've got so much to do. We wish all the best to dairy farmers."

The question was prompted by Lamb's earlier comment about the sustainability of cocoa supply in Ghana, in relation to Cadbury's decision to make Fairtrade Dairy Milk chocolate.

"How long can you go on not paying a sustainable price to farmers and expect them to continue growing products that you want to buy?" she asked rhetorically. The average age of Ghana's cocoa farmers is 56, but, for UK farmers, it is 58.

In October, Lamb will move to become CEO of Fairtrade International, the standards and certification body for Fairtrade in most major markets.

Last year, global Fairtrade sales rose by 12% to US$6.6bn, despite the weak economic climate in key markets. "It's got real traction," said Lamb.