Britons should start abandoning meat in a bid to save the environment, a world authority on climate change has said.

Changing diet was more important that cutting down car usage in the battle to reduce the average household's greenhouse gas output, it is being claimed.

Dr Rajendra Pachauri, chair of the United Nations Intergovernmental Panel on Climate Change and winner of the 2007 Nobel Peace Prize, sparked controversy by calling on families to stop eating meat for at least one day a week.

"The need to change our diet is increasingly urgent," Dr Pachauri said.

"Meat production represents 18 per cent of global human-induced greenhouse gas emissions, including 37 per cent of global methane emissions, which has 23 times the global warming potential of carbon dioxide and 65 per cent of nitrous oxide, which has 296 times the warming potential of carbon dioxide."

Government ministers and farming groups disagreed with Dr Pachauri's comments, saying the meat industry had been unfairly targeted.

Health minister Ben Bradshaw said: "I haven't looked at the details, but I suspect meat consumption is not the biggest contributor to climate change.

"There are a lot of other human activities we can change first that will help with climate change."

The National Farmers Union said "simplistic measures" to reduce meat consumption will actually "create more problems than they solve".

© Independent Television News Limited 2009. All rights reserved.