Warning: Dr Rajendra Pachauri, joint winner of the 2007 Nobel Peace Prize

Everyone should have one meat-free day a week to help save the planet, a leading expert on global warming has claimed.

Dr Rajendra Pachauri, who chairs the United Nations Intergovernmental Panel on Climate Change, said meat farming produces enormous amounts of greenhouse gases.

The environmental scientist, joint winner of the 2007 Nobel Peace Prize, said sticking to vegetables once a week would have more beneficial effects than reducing car journeys.

'Give up meat for one day (a week) initially,' the Indian economist recommended.

'In terms of immediacy of action and the feasibility of bringing about reductions in a short period of time, it clearly is the most attractive opportunity.'

He said while the world looks for ways to reduce greenhouse gases, 'growing global meat production is going to severely compromise future efforts'.

Dr Pachauri said that 18 per cent of the world's greenhouse gases come from livestock.

Methane, a much more powerful greenhouse gas than carbon dioxide, is produced by 'belching, flatulent livestock', according to environmental research organisation Worldwatch Institute.

World meat consumption is set to double in the next 20 years as developing countries such as China and India become more prosperous and eat more meat.

A U.S. study has shown an average household would reduce the impact of their greenhouse gas emissions by more if they halved their meat consumption than if they halved their car usage.

But Dr Pachauri's remarks were rejected by health minister Ben Bradshaw, who said in a TV interview: 'I suspect meat consumption is not the biggest contributor to climate change.

'There are very sensible reasons to have a healthy balanced diet, and I think some people eat too much meat, but I think there are other more useful things one can do to reduce one's carbon emissions.

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

Critics argued that meat production in the UK is more environmentally friendly than many parts of the world, such as Brazil, where rainforests are bulldozed to rear cattle.

According to food writer Joanna Blythman, 'wet, green Britain' is highly suitable for livestock and 'otherwise useless land can be grazed by cattle, sheep, goats, deer and other game'.

She added: 'Try telling the Masai tribesmen who have reared livestock for millennia that they should plough up scrubby Kenyan savannah and plant millet.'

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

Stuart Roberts, director of the British Meat Processors Association, said: 'The British meat industry already takes its environmental responsibilities very seriously and I believe methane levels on UK farms are actually falling already.'