None of Britain's eight biggest supermarkets are as environmentally friendly as they could be, a new study from the National Consumer Council (NCC) claims.
The NCC research ranked the nation's grocery sector leaders on four environmental criteria – their efforts on cutting food transport and waste and encouraging the development of sustainable resources sustainable farming.
Waitrose came top of the class, earning a B rating from the study, while Sainsbury's and Marks and Spencer ranked a C. Tesco, Asda and the Co-op were D-rated while Morrisons and Somerfield came last of all, receiving an E rating.
"We all need to understand that food is the typical household’s number one contributor to climate change," the NCC's chairman, Lord Whitty, commented.
"By throwing away ten billion carrier bags each year and transporting carrots from Egypt and strawberries from New Zealand, we hit the environment hard. But shoppers are increasingly keen to do their bit. Now, we make it clear how supermarkets could make greener choices easier for everybody."
Britain's largest supermarket chain, Tesco, dismissed the research as providing "a mere snapshot of the shopping trip", accusing it of painting a "misleading picture" which "fails to highlight the many green initiatives and products that we offer our customers".
"We already know that these issues are becoming increasingly important to our customers," the Tesco statement said.
"There is always more to do but we have announced an ambitious plan and have achieved much already."
The Conservatives have responded to the NCC study by arguing that, while it showed the "immensely powerful" impact consumers can have, "the consumers can only exercise this power if they are given a clear choice, which is not happening in most supermarkets".
"The Conservatives have consistently petitioned for better labelling standards so that consumers know what they're buying," shadow minister for the environment Greg Barker said.
The Department for the Environment, Food and Rural Affairs (Defra) had no immediate comment on the survey.