Serious concerns have been raised by the RSPCA following undercover footage recorded by an animal welfare group at two Norfolk farms.

The Animal Equality action group revealed images filmed at farms run by the East Anglian Pig Company (EAP), based near Norwich, which appeared to show pigs being hit and kicked.

The EAP is approved by the RSPCA's Freedom Food and works within the Red Tractor Assurance Scheme which promotes standards within the food industry.

Animal Equality said the footage was recorded during one month by an undercover investigator at Little Thorns weaner unit near Swaffham and The Piggery at Didlington, near Mundford, both managed by EAP.

An EAP spokesman said it was now carrying out a full internal investigation into the handling of livestock, but added the RSPCA had visited both farms involved in the investigation last week and given each a 'clean bill of health'.

A spokesman for the RSPCA confirmed an inspector visited the farms on April 19, as soon as it was made aware of the footage.

It had decided the best way to address concerns was to work with the company and the RSPCA would not be prosecuting the firm, she said.

'We have serious concerns at some of what is shown in the footage taken by Animal Equality,' the spokesman added.

'It raised a number of concerns, including poor handling of sows and younger pigs, inappropriate methods of culling and poor implementation of culling practices, using methods not in line with Pig Veterinary Society guidelines.

'We believe that some of the sick pigs shown in the footage should also have been culled and there was evidence of poor practice when trying to remove an abscess from a sow.

'The RSPCA was also very concerned that a sick sow appeared to have been left in an open area with twine tied around the jaw, but with no evidence that immediate culling was about to take place.

'This clearly requires further investigation of the circumstances.'

She said an 'urgent' meeting was planned with EAP, and regular unannounced meetings would be carried out at the farms.

A vet speaking on behalf of Animal Equality, Andrew Knight, said workers at the farms were seen 'repeatedly physically and verbally abusing pigs', while others were seen with tumours, possible fractures and difficulty breathing.

'No reasonable person could fail to be appalled and disgusted by the cruel and callous treatment frequently endured by these highly intelligent, sensitive animals,' he said. 'The public would be shocked if it knew the truth about the conditions in which these pigs were raised.'

The RSPCA said it also had concerns that the footage had been released by Animal Equality some four months after filming.