An animal rights activist has been jailed for eight years for blackmailing companies linked to an animal testing laboratory.

Gavin Medd-Hall, of Selwood Road, Addiscombe, was one of seven campaigners who intimidated companies associated with Huntingdon Life Sciences in Cambridgeshire.

They used criminal damage, bomb hoaxes and claimed employees were paedophiles during a six year reign of terror between 2001 and 2007.

This afternoon, at Winchester Crown Court, Mr Justice Butterfield sentenced 45-year-old Med-Hall to eight years imprisonment.

He called their campaign "urban terrorism" and a "relentless, sustained and merciless persecution" which had made the victims lives a "living hell".

He said he accepted that computer expert Med-Hall, and his fellow conspirators, had genuinely deeply held beliefs that animal testing was wrong, and had the right to protest against it.

But he explained: "You are not going to prison for expressing your beliefs, you are going to prison because you have committed a serious criminal offence."

The group were members of Stop Huntingdon Animal Cruelty (SHAC), which was based near Hook, Hampshire, and targeted companies in the UK and Europe that either supplied or had secondary links with Huntington Life Sciences.

About 40 companies were victimised and the total cost of damage and increased security was £12.6m, not including loss of profits, the court was told.