Farmers have claimed they are living in fear after receiving death threats from vegan activists, while meat industry groups have held meetings with anti-terrorism police to discuss how to manage the militant campaigners.

The groups say action by vegan activists, some of whom use abusive language and send threats, has become more intense in recent months.

Norman Bagley, of the Association of Independent Meat Suppliers, said: "The activists over the past 18 months have become much more violent.

"We've had situations of activists lying down in front of lorries, holding their children up to pig wagons, which is irresponsible whichever way you look at it."

Paul Tompkins, a Yorkshire dairy farmer, said he had spoken to fellow farmers who had been left "distressed" after activists broke into their farms overnight to film their animals.