The Co-operative Group plans to switch all its own-brand teas to Fairtrade and stop selling eggs from caged hens.

Co-op head of ethics and sustainability Paul Monaghan said the changes, which also include reducing the amount of glass it uses in its wine bottles and banning more pesticides from its products, would re-establish the group as “the number one ethical retailer in Fairtrade”.

Co-op started stocking Fairtrade food products 10 years ago. British consumers now spend about£400 million a year on Fairtrade goods, up from£290 million in 2006.

Marks & Spencer, Tesco and Sainsbury’s either surpassed or came close to equalling Co-op’s Fairtrade sales in recent years.

Co-op will incur extra costs as a result of the ethical offensive, such as paying a higher price for free range and organic eggs.