The British retailer plans to remove some 60 million single-use bags from its shops, the equivalent of 340 tonnes of plastic, in the first period of phasing-out, the source said.

The agreement envisages replacing an overall 180 million plastic bags over three years, the source added.

The Co-op was not immediately available for a comment.

The move is part of the Co-op's plans to cut the use of plastics in its stores and use more recycled plastic products.

Supermarkets have come under increased pressure to cut their use of plastic as images of littered oceans and beaches become commonplace, shocking both consumers and shareholders.

Since October 2015, large retailers in England have been legally required to impose a charge for single-use plastic bags, a measure which the government says has seen plastic bag sales in England’s seven biggest supermarkets drop by 86 percent.

(Reporting by Stephen Jewkes)