World Animal Protection has accused the Tesco Lotus supermarket chain, Tesco Group’s second largest business outside the UK, of selling pork products from farms where pigs are kept in cages “no bigger than a fridge”.

Sow stalls have been banned in the UK since 1999.

Tesco said no Thai pork is sold in the UK. However it said it was working with its suppliers in the region to “explore” how it could move sows “out of stalls and into group housing”.

World Animal Protection is calling on Tesco to introduce a global pig welfare policy “to stop this barbaric practice on farms that supply its stores worldwide”.

Ian Woodhurst, World Animal Protection’s farming campaigns manager, said: “Why should a mother pig have to suffer under the Tesco brand just because she’s been born and raised in Thailand?

“She would normally roam around foraging for food, socialise with other pigs and build a nest for their piglets. On a factory farm she cannot do any of this, trapped in a tiny steel cage where she can barely move.