Compassion in World Farming (CIWF) and 206 members of the public, the majority of whom appeared to be supporters of CIWF, challenged whether the claim "Red Tractor Pork is High Welfare Pork" that appeared in three advertisements was misleading and could be substantiated.

AHDB explained that the Red Tractor scheme was owned by Assured Food Standards, a British organisation that promoted and regulated food quality.

The quality mark scheme involved animal welfare assurance for the whole supply chain from farm to the retail outlet, unlike other schemes that predominantly concentrated on food safety.

AHDB said 92 per cent of farms in the UK were members of the Red Tractor scheme accounting for 40 per cent of pork sold in the UK, with 98 per cent of the remaining 60 per cent of pork sold in the UK coming from EU exporting countries.

They said Red Tractor pork was high welfare compared to pork from other EU exporting countries and believed that consumers would understand that Red Tractor pork was high welfare compared with other pork on the UK shop shelves. AHDB believed EU legislation prevented them from making a direct comparison with imported pork.

AHDB said the scheme was the only one to provide whole production chain welfare assurance, with Red Tractor farms subject to rigorous annual inspection, random spot checks and their pork the only pork on EU shelves subject to quarterly veterinary welfare audits. They said farms in the EU exporting countries underwent less frequent and rigorous audits.

They explained that Red Tractor standards did not permit pig castration, used to rear pigs to heavier slaughter weight, and the UK law banned the use of sow stalls, which were metal cages in which dry sows were kept separated from other pigs during their pregnancy. These cages also prevented the sow from being able to turn around. They said both practices were still currently widespread in the EU exporting countries.

AHDB explained that farrowing crates were permitted on Red Tractor farms, which they said were used to protect the welfare of piglets.

Sows were often kept in individual farrowing crates in the days immediately following birth up until weaning to help reduce piglet mortality as sows were less likely to crush their own piglets.

They cited evidence that showed piglet mortality rates were higher in those countries that did not use farrowing crates. They understood that Defra (Department for Environment Food and Rural Affairs) was funding research to develop and test commercially viable farrowing systems that did not closely confine the sow and also provide adequate protection to piglets, but considered that until then the risk of piglet mortality in alternative farrowing systems remained unacceptably high.

AHDB said the Red Tractor standards required stock keepers who used farrowing crates to provide nesting material, unless it was likely to cause hygiene issues that could affect the physical health of the animals.

AHDB said the Red Tractor scheme was very active in the promotion of suitable manipulable materials to be provided for the pigs and the quarterly inspection regime ensured compliance to their standards.

Access to manipulable materials, including straw, hay, sawdust, mushroom compost and peat, and non-organic materials such as wood, ropes, balls or chewing sticks, was important as it allowed pigs to engage in their natural investigation and foraging activities.

They said the Red Tractor standards made clear that non-organic materials would not satisfy all of the pig's needs and went beyond the EU Directive 2008/120/EC 'Laying down minimum standards for the protection of pigs' by prohibiting the use of tyres containing metal or wire.

The standards made clear that chains alone were not acceptable, that objects must be shown to be of interest to the pigs and within easy reach, and for the pigs to slowly destroy the object it must be malleable.

AHDB maintained that a significantly greater proportion of Red Tractor pigs had access to straw, which was the most common manipulable material.

AHDB maintained that Red Tractor members had a high standard of accommodation systems, which were usually divided into three types, fully slatted, partly slatted and solid concrete floors.

They said their standards allowed for the use of slatted floors, in accordance with the standards set out in the EU Directive, although they understood that the CWF were opposed to their use. AHDB argued that their standards stipulated that floors must be kept well maintained to prevent injury and distress and contain a well-drained lying area.

Slatted floors helped to maintain hygiene as excreta could fall between the slats, but nonetheless, they pointed out that the UK had the highest percentage of pigs kept in accommodation with straw bedding of anywhere in the EU. They therefore considered that Red Tractor accommodation standards significantly exceeded accommodation standards in the EU exporting countries.

AHDB described the problems with tail biting amongst pigs, which was generally accepted as an indication that pigs were suffering from low psychological welfare and could cause serious physical damage to pigs.

They said tail biting appeared to occur more frequently in systems that did not provide sufficient manipulable materials, or when different groups of pigs were mixed together, but tail biting was unpredictable and could occur even on farms with high standards of welfare.

They believed that the problem happened less often on Red Tractor farms, when compared with farms in the EU exporting countries, because Red Tractor pigs were provided with effective manipulable materials on a routine basis, a smaller percentage of farms used the slatted flooring system and their standards required that, after weaning, pigs must be kept in stable social groups with as little mixing as possible.

They explained that tail-docking could ease the risk of tail biting, which even in systems that significantly reduced the risk of tail biting, was often recommended by veterinarians.

However, the Red Tractor standards did not permit tail-docking to be carried out routinely; it was only undertaken on the recommendation of a vet for welfare reasons and in compliance with rigorous procedures. They believed that tail-docking could not be said to be inconsistent with high welfare standards.

AHDB said the reduction of sharp canine teeth by clipping or grinding shortly after birth was necessary to prevent piglets from injuring sows' udders and littermates' faces during competition for teats between suckling pigs.

They understood that tooth clipping was carried out throughout the EU and was undertaken to increase the physical wellbeing of the sow and piglets.

They said, although the pain associated with tooth clipping was considered to be fleeting, Red Tractor standards strictly prescribed the circumstances in which tooth clipping could be carried out and believed their standards went significantly beyond those set down in EU legislation.

They believed that the Red Tractor standards also went beyond EU legislation on transportation, general health and hygiene issues, nutrition, water availability and temperature.

They believed the level of scrutiny, across a broad range of welfare issues, meant that Red Tractor farms would be compliant with the Red Tractor welfare standards at all times.

The Advertising Standards Authority noted AHDB's assertion that the claim "Red Tractor Pork is High Welfare Pork" was a comparison with the pork imported from the EU exporting countries and understood that they believed EU legislation might have prevented them from making a direct comparison, but nonetheless considered that the basis for that claim was unclear from the ads.

"We understood that, due to differences in legislation and voluntary measures, the welfare of the majority of pigs in the UK exceeded the minimum standards laid down by the EC Directive. We were satisfied that, particularly in the areas of castration and sow stalls, the quality of pig welfare in the UK was high in comparison with the welfare of pigs in many European countries," said the ASA.

"We noted the Red Tractor scheme had stringent standards for their farms with spot checks and quarterly inspections to ensure that those standards were adhered to. We also noted the generally good compliance rate and, in those cases where a farm was found to have failed, the problems were speedily rectified. However, we understood that some aspects of pig farming in the UK, such as farrowing crates, tail-docking, tooth clipping and slatted floor accommodation, while better than in some EU exporting countries, were nonetheless still contentious issues. We noted the arguments for and against such practices and accepted that Red Tractor applied measures in an effort to control their use.

"However, we considered that, because it was unclear that the claim "RED TRACTOR PORK IS HIGH WELFARE PORK" was a comparative claim with imported pork, it would be understood to be a claim about the general level of pig welfare in the UK. We considered that the claim implied that there were no concerns about the welfare of pigs in the UK, whereas some areas were unlikely to be regarded as 'high' welfare. We therefore concluded that the claim was misleading.

The ASA has ordered the AHDB not to use the ads again in their present form.

Mick Sloyan, BPEX Director said: "We accept the opinion of the ASA regarding this small technicality. We will continue to promote the independently audited standards behind Red Tractor pork and pork products, including welfare, in a way that is absolutely clear to consumers."

Mr Sloyan added: "The English pig industry continues to invest in research aimed at improving pig welfare, despite the acute financial pressure we are under. We are proud of our existing welfare standards and methods of production and we are deepening our understanding of how these impact on the pigs in our care through the Real Welfare Project. This is much better for pig welfare than relying on often misplaced views of production systems."

BPEX Chairman, Stewart Houston said: "It is bizarre that at a time when the EU is trying hard to bring other Member States standards of pig welfare to something approaching the standards that we have had in the UK for over a decade, we have complaints being made by a UK organisation which claims to be focussed on improving animal husbandry across the world.

"The UK is less than 50 per cent self-sufficient in the supply of pork, bacon, ham and sausages with around two-thirds of imported pig meat produced to welfare standards which are below the UK minimum. The Red Tractor scheme allows consumers to make an informed choice as to which welfare standards they wish to support.

"The UK pig industry invested back in 1999 and has used the Red Tractor to help consumers identify high welfare quality assured pork and pork products and reward UK farmers for the additional production costs associated with high welfare pig production.

"To try and discredit or undermine the Red Tractor is to encourage more imported meat which is not produced to such exacting welfare standards."

Reacting to the ASA’s ruling, Joyce D’Silva from Compassion said: “The truth will out. This is a victory for consumers, who deserve to be able to choose higher welfare meat without being misled. Claims of high welfare are clearly a lucrative marketing tool but in this case they were overblown and misleading to the consumer.

“The “pork not porkies“ claim on the advert makes this a particularly embarrassing own-goal for Red Tractor pork.

“This is also a victory for those pig farmers in the UK who adhere to higher welfare standards like the Soil Association’s organic standard or the RSPCA’s Freedom Food.“

Ms D'Silva added: “The Red Tractor labelling scheme for pork does not guarantee high welfare and we are delighted that the ASA agrees with us that the claim was misleading. We hope the advertisers will think twice before telling porkies about their welfare standards again.“

A spokesman for the RSPCA said: "The RSPCA understands that shoppers are being bombarded with different welfare messages in the supermarket and hopefully today's ruling will help bring some clarity.

"Buying British, shopping at a family butchers or farmshop, or choosing food with labels such as 'farm fresh' or 'healthy option' is not an automatic guarantee that the food has been produced under good animal welfare standards.

"Under the Red Tractor scheme pigs can be kept on bare concrete or slatted floors with no comfortable bedding or suitable materials such as straw to root around in - not conditions which the RSPCA, and many shoppers, would equate with 'high welfare'.

"There are some really good farms in the Red Tractor scheme which go well above the basic scheme requirements to provide their pigs with higher welfare conditions but there are others which are merely working to the minimum requirements and therefore failing to meet all the pigs' physical and behavioural needs.

"However, the RSPCA shares the UK Pig Industry's concerns that a significant proportion of pork products imported into the UK from the EU and elsewhere come from pig production systems that would not meet certain key Red Tractor Scheme standards.

"We know that shoppers care deeply about the welfare of farm animals. We are pleased that the pig industry and Red Tractor scheme realise that shoppers want to choose higher welfare options and we will continue working with them to help ensure all British pork becomes a higher welfare option and, in the process, improve conditions overall for the 10 million pigs reared in UK every year."