In its latest investigation, however, Evira did find some cases of neglect on a few farms.

Following the release of the secret filming last month, inspectors found some evidence of problems with feeding and medicating the animals and one farm is under investigation by the police.

In a report in YLE on 19 December, Evira commented that it believes the current surveillance system works, under which farms are bound by a welfare agreement.

The story starts at the end of October, when it was reported that is four pig farm activists could face a court case and damages of €175,000 over secret filming at pig farms in 2009.

In all, the activists had videotaped conditions at 30 pig farms in various parts of Finland. The footage sparked a public outcry and 10 farmers had demanded compensation for mental suffering and production losses.

In mid-November, the activists were cleared of charges related to the filming.

Just a few days later, new films were released showing apparent negligence on pig farms. The videos were again shot in secret by animal rights activists – this time, on 16 farms and shot in October and November this year. The pictures appeared to show pigs in filthy pens, with sick and dead pigs left in with living ones.

Chair of the pig producers’ association, Martin Ylikännö, admitted that the videos show mistreated animals but he criticised the activists' tactics as well as the farmers' practices.

According to YLE, Evira had tightened checks on farms since the 2009 films were releases. Because of the stricter controls, more violations of animal rights standards were found than before, with one-third of those inspected in 2010 in violation of regulations. The majority of inspections were, however, made at farms where officials suspected negligent practices.

Efforts to deal with the problems are also reported to be underway within the pig industry, and slaughterhouses were told by Pirjo Kortesniemi, Managing Director of an animal disease prevention association, to stop buying from farms where problems had been detected.

The activists warned that they would maintain scrutiny of the industry. According to YLE, the activists would like to see the end of meat production altogether.

A month ago, an organisation called 'Justice for Animals' displayed dead piglets by 'The Three Smiths' statue in central Helsinki on Wednesday. The stunt aimed to draw attention to poor conditions at pork farms. Officials quickly clamped down on the activists.