Marks and Spencer is to begin charging its food shoppers for carrier bags.
Customers will have to pay 5p for plastic bags, with the money raised going to an environmental charity.
Chief executive Sir Stuart Rose said the company wanted to "make it easy for our customers to do their bit to help the environment".
Campaigners say plastic bags damage the environment. Some 13bn are given free to UK shoppers every year, and they take an estimated 1,000 years to decay.