Local food is usually more "green" than organic food, according to a report published in the journal Food Policy.

The BBC reports that the authors say people can help protect the environment by buying food produced within a 20km (12 miles) radius. They claim British consumers are not fully aware of the severe damage done to the environment by driving food long distances around the UK. Proportionately, "road miles" account for more environmental damage than "air miles", the authors claim. Therefore, the message to consumers is this: it is not good enough to buy food from within the UK - it is better if it comes from within your area, too.

A big city like London could be provided with a lot more seasonal vegetables from local farms Co-author Professor Tim Lang However, the authors admit that consumers are prevented from "doing the right thing" because of inadequate labelling. "The most political act we do on a daily basis is to eat, as our actions affect farms, landscapes and food businesses," said co-author Professor Jules Pretty, from the University of Essex, UK. "Food miles are more significant than we previously thought, and much now needs to be done to encourage local production and consumption of food."

Clean-up costs

Professor Pretty and his colleague Tim Lang, from City University, UK, painstakingly estimated the environmental "price tag" on each stage of the food production process. That price might reflect, for example, the clean-up costs following pollution, or the loss of profits caused by erosion damage. British eggs, PA The price of food is disguising externalised costs "The price of food is disguising externalised costs - damage to the environment, damage to climate, damage to infrastructure and the cost of transporting food on roads," Professor Lang told the BBC News website. The authors calculated that if all foods were sourced from within 20km of where they were consumed, environmental and congestion costs would fall from more than £2.3bn to under £230m - an "environmental saving" of £2.1bn annually.

They pointed out that organic methods can also make an important contribution. If all farms in the UK were to turn organic, then the country would save £1.1bn of environmental costs each year. Consumers can save a further £100m in environmental costs, the authors claim, if they cycle, walk or catch the bus to the shops rather than drive.

Each week, the average person clocks up 93p worth of environmental costs, the report concludes. These costs should be addressed by the government, companies and consumers, the authors believe.

Sophisticated policy

"It is going to need some sophisticated policy solutions," Professor Pretty said. "You could say we should internalise those costs in prices, so that it affects people‘‘s behaviour. That might be economically efficient but it lacks on the social justice side because it will affect rich people much less." Instead, the authors are advocating a softer approach. Consumers should make ethical choices about the food that they buy, and supermarkets should be open with customers about where their food is coming from. At the moment, as every UK consumer will know, it is impossible to tell whether your carrot has come from Devon or Scotland.

At the moment it is impossible to tell whether your carrot has come from Devon or Scotland "In the short term, our paper adds to consumer frustration," Professor Lang concedes. "The problem is we don‘‘t get the information. Food labels don‘‘t tell you the sort of information you really need to know if you want to do the right thing by the environment." Since supermarkets do know exactly where their food is coming from, Professor Lang believes they have a duty to inform their customers. Eventually, the<