Heather Mills in pig farm raid to highlight 'cruelty'

Heather Mills has revealed she entered an industrial pig farm at the dead of night as part of a campaign to highlight alleged animal cruelty.

She led a team from the vegetarian group Viva! in a raid on a Somerset farm two weeks ago.

Watch the video here

Heather crouching in the dark next to a 'caged' pig

Miss Mills went on to the farm to point out the use of farrowing crates, which she calls "cages" and "prisons".

The crates are narrow pens with concrete floors. They are used for sows when they are giving birth and suckling their piglets.

They are so narrow that the sows cannot turn around. There is an escape area at the bottom which allows piglets to run out and avoid being trampled by their mothers.

Miss Mills highlights the 'cruel conditions' that the pigs are forced to live in

But although the crates have attracted Miss Mills’s ire, they are legal and widely used worldwide.

And last night the owner of the farm she visited threatened to take her to court for trespass and suggested the Viva! team might have brought disease on to his property.

Miss Mills will is launching a campaign calling for the Government to outlaw the crates.

She will also make a specific attack on Marks & Spencer for accepting meat from farms which use the crates. She will use the message: "This is not just torture – this is M&S torture."

Illuminated by torchlight in the night-time raid

Miss Mills found time to take part in the farm raid while at the centre of the maelstrom surrounding her divorce from Sir Paul McCartney.

Footage shows her putting on overalls and disinfecting her boots before touring sheds on the farm, where 3,500-4,000 pigs are reared at any time.

Miss Mills says she is doing nothing illegal. But entering private premises without permission would appear to be trespassing, a civil offence.

She expresses outrage at the use of the crates and the general conditions in which the pigs are reared. Some 70 per cent of all pigs raised in the UK start their lives in farrowing crates.

The filming took place at Briarwood Farm, at Greinton, near Bridgwater. But owner Michael Underhill knew nothing of it until contacted by the Daily Mail. He said: "This is trespass, I intend to take legal action over this. We can’t just have people coming on to the farm whenever they choose.

"There are risks of disease being carried into the buildings. We have had some sickness in the piglets recently, we don’t know where it came from, but these people could have brought disease on to the farm. They don’t know the harm they are causing."

Pulling on her boots. But the farmer claims disease could have been brought onto his property

He said he was doing nothing wrong. "Farrowing crates are widely used. They are there to protect the piglets from being trampled and coming to harm. They are a welfare measure."

A Marks & Spencer spokesman said: "M&S has leading animal welfare standards and has been recognised for these by both the RSPCA and Compassion in World Farming.

"We are disappointed Viva! is taking this action as we met and told them before Christmas that we were phasing out the use of farrowing crates.

"All our fresh pork is already outdoor bred – which accounts for 30 per cent – and we have committed to moving to free range."

Viva! director Juliet Gellatley, a friend of Miss Mills, denied taking disease on to the farm. She said: "None of the people involved had been on another pig farm for a very long time. They wore biosecure suits and new, disinfected boots."