The new bottles will have a cloudier and greyer appearance than those that do not contain recycled plastic, the supermarket said.

However, the new hue would be a "badge of honour" for the company, although it admitted the move could put shoppers' environmentally conscious credentials to the test.

Co-op Food chief executive Jo Whitfield said: "Our customers expect us to respond to this challenge and help them make more ethical choices, and we're dedicated to doing just that.

"Making these changes will also create new uses for recycled materials which in turn gives our customers greater confidence in recycling."