Five animal rights protesters have been jailed for launching a campaign of terror and intimidation against Huntingdon Life Sciences.

Targeting businessmen who had links to the animal testing company, the protesters spread false rumours that they were “paedophiles”.

The group also sent their victims hoax bombs and soiled tampons that they allegedly claimed were contaminated with HIV.

The activists mailed letters to the neighbours of one businessman whose firm had an indirect link to the country’s largest animal research centre, claiming that he was a paedophile and that they should keep their children away from him.

The protesters were part of an organisation called Stop Huntinghton Animal Cruelty, also known as the Animal Liberation Front.

Hospital nurse Sarah Whitehead, 53, who spearheaded the campaign and was referred to as “Mumsy” by the others, was jailed for six years and was given a 10 year ban from animal rights activities.

Also jailed after admitting conspiracy to blackmail were Nicole Vosper, 22, Thomas Harris, 27, Jason Mullan, 32 and Nicola Tapping, 29.

Jailing the activists, Judge Keith Cutler said: “You are not going to prison for expressing your beliefs, you are going to prison because you have committed a serious criminal offence.”