Having announced three years ago it would be asking each sector to produce its own code, Defra says it has now changed its mind, and will continue to produce the codes itself.

"We don't care whether it's us or Defra who update the current Code of Recommendations for the Welfare of Pigs, as long as it gets done, and as long as we are involved," said NPA chief executive Dr Zoe Davies.

"The current edition was written 13 years ago. It's our industry manual and it's now seriously out of date, and that means we are missing an important opportunity to remind producers of the latest pig welfare legislation and to provide guidance on science-led best practice in pig husbandry."

NPA understands representations by vegetarian and vegan activists played no part in Defra's U-turn yesterday, rather that Defra realised the welfare codes should be the joint responsibility of Government and industry.

"The codes are designed to be a farmer-friendly way of providing up-to-date statutory information in tandem with useful advice," said Dr Davies.

"We are ready to play our part in helping Defra update the current code. Indeed we insist on having an input. We'll be pressing them vigorously to get a move on, otherwise we may have to produce our own interim code, because we're not prepared to wait another 13 years for our pig industry welfare manual to be updated."

The National Farmers' Union (NFU) said the u-turn set a "dangerous precedent".

NFU Deputy President Minette Batters said: “It’s extremely concerning to us that Defra is rescinding the jointly-owned animal welfare guidance - it sets a dangerous precedent for both government and our industry.

“Reversing considerable efforts to replace older, out-of-date guidance in the face of sensationalist pressure from campaigning groups undermines both government rationale and the importance of an up-to-date animal welfare code."