Seven animal rights extremists were sentenced to a total of 50 years imprisonment for conspiracy to blackmail after appearing at Winchester Crown Court today.

Stop Huntingdon Animal Cruelty (SHAC) co-founders Gregg Avery (41) and Natasha Avery (39) along with Daniel Amos (22), pleaded guilty to charges of conspiracy to blackmail companies they perceived to be linked to Huntingdon Life Sciences PLC (HLS). Gregg and Natasha Avery each received nine years, Daniel Amos was sentenced to four years.

SHAC co-founder Heather Nicholson (41) together with Gavin Medd – Hall (45), Daniel Wadham (21) and Gerrah Selby (20) were found guilty by a jury after a three month trial last December and were sentenced to 11 years, eight years, five years and four years respectively.

The conspiracy to blackmail charges were bought against the seven as a result of an international police investigation known as Operation Achilles, which targeted criminal activity associated with animal rights extremism culminating in the arrests of 32 people in May 2007.

When passing the sentences today, Mr Justice Butterfield said "You are not going to prison for your beliefs, you are not going to prison for expressing these beliefs, you are going to prison because each one of you has committed a very serious criminal offence.

"You cloaked your activities with what in my judgement was a hypocritical sham pretence that SHAC...was a vehicle for legitimate lawful protest in an area of public concern. It was nothing of the sort. It was a vehicle used to terrorise ordinary decent traders carrying out perfectly lawful businesses."

Following the sentencing, senior investigating officer Detective Chief Inspector Andrew Robbins of Kent Police said: "We welcome the sentences passed today by Mr Justice Butterfield at the Crown Court in Winchester. These sentences appropriately reflect the very serious and sustained nature of the campaign of blackmail masterminded by a small group of individuals.

"It is clear from the guilty pleas of three of the extremists, and from the overwhelming evidence which led a jury to convict the four others, that their actions had nothing to do with freedom of expression or lawful protest.

"It took a great deal of courage by the victims, not only to resist this campaign, but also to give evidence in court. It is important to remember they suffered a campaign of intimidation that didn't just affect them but their families and the communities in which they lived.

"These sentences are the latest to be passed as a result of Operation Achilles, the largest police operation investigating animal rights extremists in the UK. This investigation demonstrates the continuing determination of law enforcement agencies and the Crown Prosecution Service to tackle animal rights extremism.

"Most campaigners remain peaceful and stay within the parameters of the law and we hope these sentences act as a warning to the minority who believe they can engage in criminal activity to further their cause."