Wm Morrison is launching a new scheme to help slash the 12m tonnes of food waste created in Britain each year.

The initiative from the Bradford-based supermarket giant — called Great Taste, Less Waste — is designed to tackle the 6.7m tonnes of food that ends up in customers’ rubbish bins. The supermarket group plans to put up signs in its stores and post tips and advice on its website — such as putting apples in the fridge to make them last 14 days longer.

The project is the latest salvo from the big grocery chains in what has become the equivalent of an environmental arms race.

Supermarkets have competed for a place on The Sunday Times Green List for the first time this year. Tesco and Asda blazed

a trail for other high-street retailers and have been rewarded for their efforts with rankings among the 60 Best Green Companies in Britain.

The big four — Tesco, Sainsbury’s, Asda and Wm Morrison — are competing to be seen as the greenest, attempting to measure up to the environmental aspirations of some of their customers while seeking to inspire others to go green.

It is two years since Tesco pledged to put carbon labels on all its products, while Marks & Spencer launched Plan A — a 100-point programme to improve its environmental credentials. The two high-street giants started a race to become the greenest retailer in Britain.

Back then, the City largely dismissed the initiatives and questioned whether they were simply marketing gimmicks. But it has since become clear that, for supermarkets, going green is not about pure altruism or even good PR — it is also about the bottom line.

Retailers have discovered that the eco-agenda saves them money and brings in customers. That drive is likely to accelerate during the next five years as the British and American governments examine a range of green taxes that could hit companies that don’t embrace change..

It all means that, far from slipping down the agenda during the recession, green issues are more important than ever.

Alison Austin, environment manager at Sainsbury’s, said: “We haven’t dropped anything during the recession. Everything we do is either really good for the commercial bottom line or it is something that customers care about.”

This was borne out in the company’s latest results, published last week, which showed annual profits up 11% to £543m. Though the supermarket credited the increase in profits largely to its Switch and Save campaign, which promotes lower-priced Sainsbury’s-labelled products, supply-chain efficiency programmes helped to offset some 75% of the total cost inflation from wages, property and energy costs.