Sir Paul McCartney and his family are asking people to go meat free once a week in a bid to combat climate change.

He has been joined by daughters Stella and Mary McCartney, and a host of stars such as Coldplay's Chris Martin, Hollywood stars Kevin Spacey and Woody Harrelson and actress Joanna Lumley in urging us to go veggie one day a week.

The aim of Meat Free Monday is to reduce greenhouse gas emissions from the world's livestock population.

According to the United Nations Food and Agriculture Organisation, meat production is responsible for 18 per cent of greenhouse gas emissions. This compares to an estimated 13 per cent from transport.

Sir Paul said: "Many of us feel helpless in the face of environmental challenges, and it can be hard to know how to sort through the advice about what we can do to make a meaningful contribution to a cleaner, more sustainable, healthier world.

"Having one designated meat-free day a week is a meaningful change that everyone can make, that goes to the heart of several important political, environmental and ethical issues all at once."

He added: "We should care about climate change because if we don't, we are going to leave our children and their children in a hell of a mess."

Sir Richard Branson, who is also backing the campaign, said: "I love eating meat, but I love our planet even more, so I will join this campaign and stop eating meat at least one day a week."

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