The methods it will use are to put warning stickers on imported pork (to inform shoppers of the dual standards operated by most retailers) and to blockade retail distribution depots.

BPISG says that given the provocative remarks currently issuing from supermarket buyers (‘Your members haven’t got the stomach for blockades any more’) it won’t feel bound by Queensberry Rules.

It says the supermarkets leading the stampede away from British welfare standards are Tesco, Asda and Sainsbury’s.

‘We have noticed a marked increase in intimidatory techniques adopted by the supermarkets when dealing with the meat processor suppliers. All the feedback we are getting indicates Tesco is feeling particularly confrontational at present.’

Sean McCurley, Tesco category director for meat, fish and poultry, has resigned from the board of the British Pig Executive.

BPISG says it is careful to exclude Waitrose, M&S and Budgens from its criticisms, as these retailers continue to demonstrate their commitment to British quality standards.

• Instead of being kept in narrow stalls without enough room to turn round, British sows are loose-housed in straw. In Britain pigs are not castrated without anaesthetic, nor are they fed on swill or animal oils.
  
  

• Surveys by the British Pig Executive have demonstrated that a substantial majority of supermarket customers are opposed to supermarkets stocking food that falls below United Kingdom standards.