Investigators from Compassion in World Farming found 80 per cent of farms across five European countries engaging in illegal practices such as barren pens and routine tail-docking.
In one of the biggest undercover inquiries into pig-farming, CIWF visited 60 farms across five big pork-producing states, Spain, the Netherlands, Germany, Hungary and Britain.
In 48 farms, farmers had cut the tails off pigs to stop them biting each other, despite EU rules restricting tail-docking. Some 47 failed to provide anything for the pigs to root around in, despite an EU requirement to provide "environmental enrichment" such as straw. Most farms made widespread but legal use of metal cages for confining pregnant pigs. Overall, Spain had the worst conditions, followed by the Netherlands, Germany, Hungary and Britain.
Conditions are so bad, some pigs are resorting to cannibalism.
Jaime Oliver is doing a show about the issue in Britain.