The UK's supermarkets have taken action to become more environmentally friendly, but need to go further to become truly green, a new report has said.
Sainsbury's, Marks & Spencer and Waitrose topped their rivals in being recognised as the most environmentally aware. The three companies each received a B rating in the latest green league table of retailers published by the National Consumer Council (NCC).
Asda and Tesco also improved their green credentials, both moving from a D to a C grade in recognition of their efforts to improve sustainability within their stores. Likewise Morrisons and Somerfield improved their ratings from E to D.
However researchers said that not one of the supermarkets had received top marks for the proportion of UK in-season produce on sale in their stores.
The NCC also said it had found "wildly varying" performance in terms of the use by retailers of unnecessary packaging and plastic bags.
It also criticised the price of energy-efficient light bulbs. The report found that the cheapest energy-efficient light bulbs available in Sainsbury's and the Co-op both cost more than 20 times the price of traditional light bulbs.
The NCC is now calling for the country's supermarkets to go even greener by stocking a wider range of low-cost energy-saving light bulbs, phasing out the use of plastic carrier bags and making greater use of recycled materials in packaging.
Supermarkets are also being urged to sell more fish from sustainable sources and to adopt tougher targets to increase the amount of organic and low-chemical foods on sale.
NCC chair Larry Whitty said: "The food we eat is responsible for one-third of our impact on climate change so its vital that the big supermarkets make green shopping much easier.
"NCC's research has spotted important signs of progress right across the market, with all stores now beginning to embrace sustainability. But much remains to be done if supermarkets are to become truly green grocers," he added.