Compassion in World Farming, Eurogroup for Animals, Humane Society International, PROVIEH and Vier Pfoten wrote to Mr Barroso, expressing deep dissatisfaction with the failure of the Commission to secure compliance by the EU pig sector with important provisions of EU legislation on the welfare of pigs.

The welfare provisions in question ban routine tail-docking and require pigs to be given enrichment materials such as hay or straw to enable them to engage in their natural behaviours of investigating and manipulating their surroundings.

The letter to the President detailed information and pointed out that since this legislation came into force in 2003, a massive 2000 million pigs have suffered poorer welfare than they would have done if the EU’s pig sector had complied with the laws on enrichment and tail docking.

According to the groups, each day over 500,000 new pigs are added to those who have experienced substantially poorer welfare than necessary because of the authorities’ failure to rein in the pig sector’s lawless behaviour.

The reply from the President’s Office said, "Mr Barroso received the letter with interest and has taken note of its contents."

Peter Stevenson, Chief Policy Advisor for Compassion in World Farming, said: "The President’s disappointingly brusque and disinterested reply exposes a deplorable indifference towards European citizens’ concern about animal welfare and law enforcement. It is totally unacceptable for the Commission President, when given detailed evidence of widespread breaches of EU law by pig producers, to decline to act.

"A Eurobarometer Survey on attitudes to animal welfare reports that, on a scale of one to ten, EU citizens give animal welfare an importance rating of 7.8. When five leading animal welfare organisations write on behalf of those EU citizens, drawing attention to serious breaches of animal welfare legislation, they deserve a full and considered response."

Compassion has previously notified the Commission of breaches of the Directive on pig welfare, discovered during investigations in 2008 and 2009. In 2013, the charity undertook a further investigation, exposing continued breaches of legislation and showing no improvement in compliance since previous investigations.

Council Directive 2008/120 (Pigs Directive) requires that pigs be given enrichment materials. It also bans routine docking of tails, which is scientifically proved to be unnecessary if the pigs are kept in good welfare conditions, as they are then not driven to bite the tails of other pigs.

In 2013, Compassion visited 45 farms in six member states: Italy, Spain, the Czech Republic, Ireland, Cyprus and Poland. Of the 45 farms, 44 were breaking rules on enrichment provision and tail docking, blatantly flouting European law. These breaches have been reported to the European Commission but no action has yet been taken.

Mr Stevenson added: "The European Union’s collective failure to act on these breaches is an inexcusable mockery of the legal system. Why create a law if not to enforce it? We will continue to urge the Member States and the Commission to belatedly enforce the Pigs Directive, and await an adequate response from the President to our letters."