Animal rights extremists are turning up the heat in Britain — clashing with police, attacking research labs and their employees and now broadening their base of potential targets.

So the government has announced new measures to crack down on such activists, saying those who protest outside the homes of people associated with animal testing will be arrested and tightening up the definition of harassment.

At Oxford University (search), the company building a lab for cancer, Alzheimer’s disease and Parkinson’s research, pulled out of the project following a campaign of intimidation.

Pharmaceutical companies say the harassment has cost the country close to $2 billion and is strangling the development of new, life-saving drugs.

Animal rights groups predict the British government’s initiative will backfire. They say it’s a small minority of animal rights activists who turn to violence, but expect the government’s new plan will drive more people to use extreme tactics in response.

Click on the video box near the top of this story to watch a report by FOX News' Amy Kellogg.