A second major retailer has announced plans to start selling milk in bags in an effort to cut the millions of plastic cartons discarded every year.

A second major retailer has announced plans to start selling milk in bags in an effort to cut the millions of plastic cartons discarded every year.

Sainsbury's will start selling the recyclable bags of milk and a specially designed reusable jug this week.

The move follows a successful trial of milk bags by Waitrose that has been running for a year.

Campaigners hope the scheme will help to abolish plastic milk bottles, thereby reducing landfill and saving the energy used in their manufacture.

Britons currently consume approximately 180 million pints of milk a week, of which at least two-thirds are sold in plastic bottles, which began to replace Tetra Pak cardboard containers in the nineties.

It has been estimated that only one in four plastic bottles is recycled.

The Co-operative first tried to introduce milk bags in the seventies and Sainsbury's made its first attempt seven years ago, but both met consumer resistance.

Sainsbury's will initially sell milk bags in 35 stores, expanding to 500 outlets within the next year.

Sainsbury's spokeswoman Emma Metcalf-King said: "Milk is the biggest-selling product by unit in Sainsbury's stores, with over eight million litres sold every week.

"This is a revolution in milk packaging which potentially cuts waste by a massive 75%.

"Milk in a bag is an incredibly simple way for families to reduce their environmental impact."