Vegans and vitriol

Why do vegans and veganism provoke so much anger amongst some meat-eaters? Sociology lecturer Catherine Happer, from Glasgow University, Chris Snowdon, from the Institute of Economic Affairs think-tank, and Sarah Boseley, health editor of the Guardian newspaper, explain why they think giving up animal products is such an emotive issue.

(Picture: An animal rights activist wearing a pig mask. Credit: Getty Images)