A man has been jailed for a record four years for a campaign of intimidation against an animal testing company.
The activists wore skull masks to protest at a haulage firm
Mark Taylor, 39, from Wakefield, West Yorkshire, targeted firms working with Huntingdon Life Sciences, in Cambridgeshire, the Old Bailey heard.
His wife Suzanne, 35, was jailed for 30 months and Teresa Portwine, 48, of New Addington, Surrey, received 15 months.
All three had admitted conspiracy to interfere with a contractual relationship, at an earlier hearing.
The offence was created by the Serious and Organised Crime and Police Act 2005 and designed to stop staff being subjected to harassment by protesters.
The judge said their intention was clearly to "intimidate and frighten" ordinary members of staff.
All three activists were members of a group called Stop Huntingdon Animal Cruelty (Shac).
They took part in a campaign of intimidation against businesses in the summer of 2005, during which they attacked up to 25 separate targets, including a haulage firm and catering company.
Firms perceived to be working with Huntingdon Life Sciences (HLS) were singled out on Shac's website, along with photographs of individual workers.
Staff were left terrified when up to 12 protesters at a time invaded their offices shouting "murderers".
And one company in Peterborough dropped its contract with HLS altogether after it was attacked by five demonstrators wearing skull masks.
Taylor himself attended 20 demonstrations - 17 after he was arrested and was on bail.
Plea to judge
Housewife and mother-of-two Suzanne Taylor was said to have taken part in the campaign for three weeks, while Portwine, a kitchen consultant and mother-of-five, is believed to have left as soon as police discovered her identity.
Unemployed Taylor told the judge he regretted his actions and said he never meant anyone to be fearful of him.
He maintained he was deeply committed to animal rights, but promised to devote his time to his local dog shelter in future rather than going on demonstrations.
However, the judge described his behaviour and that of his co-defendants as "violent and intimidatory".
Mr Justice Goldring said the sentences must act as a deterrent, adding: "Throughout, I am sure the intention was to intimidate and frighten those at their lawful place of work."
One firm dropped its HLS contract after an attack by masked demonstrators
HLS carries out medical research on animals which the government has described as vital, but it has come under repeated fire from animal rights groups.
Iain Simpson, from Pro-Test which supports animal testing, told the BBC he hoped the sentences would not deter legitimate activism, but would put off those intent on violence.
"You can't break into someone's offices and go around filming, intimidating and abusing the staff," he said.
"It's thuggery, it's intimidation and it's against the law.
"You can still demonstrate peacefully, you can still demonstrate legally."
After the case, Director of Public Prosecutions Sir Ken Macdonald said he would not hesitate to pursue anyone who sought to intimidate companies.
"Everyone is entitled to conduct lawful business, to work and to purchase goods and services without fear of intimidation and disruption," he said.
The three activists were arrested following a nationwide inquiry by the police National Domestic Extremism Team.
Assistant Chief Constable Anton Setchell, the team's co-ordinator, said: "The actions of these people who have been sentenced today went well beyond what is lawful and acceptable."
The first person to be convicted under the new laws was cancer scientist Joseph Harris, 26, who was jailed for three years last September.