THREE animal rights extremists were jailed for twelve years each yesterday for waging a six-year hate campaign that included the desecration of a grandmother’s grave.

Jon Ablewhite, John Smith and Kerry Whitburn admitted their leading roles in intimidating and attacking the owners of Darley Oaks guinea-pig farm in Staffordshire only two weeks before they were due to stand trial.

Josephine Mayo, a fourth extremist who admitted similar offences, was jailed for four years.

Judge Michael Pert, QC, said that the four offenders had disinterred the remains in the low point of a “campaign of terror” that ruined many people’s lives.

He said: “You kept the family on tenterhooks as to when you would return her and you used as a weapon the threat that you would do the same again. I am firmly of the view that each of you does represent a danger to society.”

The sheer weight of evidence against all four was disclosed yesterday as they were sentenced at Nottingham Crown Court after admitting during a hearing last month to conspiring to blackmail the family.

The three men, who all had previous convictions, were leaders of the campaign that culminated in the theft of Gladys Hammond’s body. She was the mother-in-law of Christopher Hall, co-owner of the farm in Newchurch, Staffordshire, that bred guinea-pigs for medical research. Her remains were recovered last week after Smith, considered the most hardened of the four activists, disclosed their location in what proved to be an unsuccessful attempt to reduce his sentence.

Anthony Glass, QC, for the prosecution, described the campaign as prolonged and vicious. He said that Mrs Hammond’s jawbone was left at the graveside. Ablewhite, 36, a teacher living in Manchester; Smith, 39, of Wolverhampton; Whitburn, 36, of Birmingham; and his girlfriend, Mayo, 38, also of Birmingham, had believed that they were untouchable, but had made numerous errors that eventually led to their arrests.Mayo was caught on closedcircuit television buying a petrol can that was used to make an explosive device left at the home of Mr Hall’s daughter, Sally-Ann Hall, 28. A map book found in her car had a broken spine and opened immediately on to Miss Hall’s address.

Documentation stolen in a burglary at the farm in 1999 was found in Ablewhite’s home and his computer had an image of Miss Hall’s home. His mobile phone contained the registration numbers of cars that had been attacked. He also sent an e-mail of personal details of family and friends of the Hall family, which described the action as an “ongoing holocaust”.

A manual typewriter, stencil, handwriting linked with abusive letters and photocopies of an anatomy book showing a skull with its jawbone removed, were found at Whitburn’s house. Footage of the burglary in 1999 and a sheet of car registration numbers and personal details of the Halls, including birth, marriage and death certificates, were discovered at Smith’s home.

Staffordshire Police made an appeal on Crimewatch in March last year. Immediately after the programme, Smith, Ablewhite and Whitburn drove to woodland near the guinea-pig farm. When stopped by police the next day, the car was found to contain a collapsible spade, headlamp, balaclava and wet camouflaged clothing linked to Ablewhite.

A text message sent by Smith while the men were in the woods referred to “flies hovering, could be a while”. Police now believe that they were moving the body.

Harrowing witness statements were read to the court that brought home the horror and relentlessness of the attacks. Hundreds of letters were sent to victims including the Halls’ cleaner, May Hudson, threatening to dig up her recently deceased husband. Others were hoax invitations, sympathy cards or birth announcements. When Mr Hall’s mother died, a card was sent saying: “One down, seven to go.” Letters offered to reveal where the body was if trading stopped, but the location was not revealed even when the farm closed in January.

Detective Chief Inspector Nick Baker, who led the investigation, said: “It became clear that we were dealing with lawless people who were ruthless in their aims. Ablewhite, Whitburn and Smith were not on the fringes of the animal rights campaign. But, despite their meticulous planning, the offenders made several mistakes. They refused to go to ground following the desecration.”

The police bill for protecting the farm and surrounding community and investigating the threats and attacks reached more than £3 million.

In a witness statement, Mr Hall said that he had spent about £400 a week on security, including electric fences, dogs and cameras. He was critical of the initial stages of the response, saying: “It became a battle to survive. Often when charges got to court people got off, or the CPS wouldn’t even prosecute. It seemed we have no support from the Government when they were taking 60 per cent of the guinea-pigs we were producing. My family and I may as well have been in prison for six years. These activists are terrorists.”

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