Animal rights activists could face five years in prison for targeting research centres under new government measures.
The bill makes causing "economic damage" through intimidation a criminal offence
Trade and Industry Secretary Patricia Hewitt told the BBC the laws were to combat a growing problem threatening medical research in the UK.
But Adolfo Sansolini, Chief Executive of the British Union for the Abolition of Vivisection (Buav), is concerned the legislation will restrict peaceful protesters' freedom of expression.
PATRICIA HEWITT MP, TRADE AND INDUSTRY SECRETARY
We want Britain to be the best place in the world for science, and that's because British scientists, who are outstanding - we want them to be the making the great breakthroughs in treating Alzheimer's, for instance, and Aids and cancer; diseases like that.
And we do also want the jobs and investment here and that is what's being put at risk by these animal rights extremists.
The people I'm listening to are people like Mr and Mrs Hall whose farm was the target; and families, friends and employees who were the subject of nearly 460 different instances last year.
One of the family graves was desecrated - Mrs Hall's mother's body was dug up from the grave.
Those are the people that we are determined to protect and I think, frankly, anybody, whatever they think of animal research, would agree that they should be protected.
We've got the strongest laws in the world to protect animals which are being used for medical research.
If it isn't necessary to use them then we've banned it; we've invested very substantially in alternatives to animal testing to try to reduce it further in future.
But where it is necessary it takes place only under the most controlled circumstances, only in licensed premises and it is lawful.
And what we can't have is these extremists going way beyond the bounds of peaceful protest into these vicious campaigns of intimidation, which I'm afraid have not been stopped by individual laws dealing with individual acts.
It is the concerted campaign which we've got to stop.
ADOLFO SANSOLINI, BRITISH UNION FOR THE ABOLITION OF VIVISECTION
We also want Britain to be the best place for science, but research using animals is not what we and several scientists would define as good science.
Also, it is very often not for medical research - lab animals suffer and die every year for as trivial reasons as a new carpet shampoo going on our shelves.
Virtually all of the breakthroughs in the understanding and treatment of Aids have come from studies not involving animals.
We are very concerned that these extra proposals could limit the right to freedom of expression
And species' differences mean research into cancer and Alzheimer's involving animals are a poor predictor of these diseases in humans, and scientifically dubious.
We will be looking at the detail of the government's proposals very carefully to make sure our right to protest and inform the public is not restricted.
The Buav is a non-violent campaigning organisation that opposes violence of all kind.
We believe the tactics used by a very small minority of protesters, and focused on by the media, undermine the messages, damage the reputation of, and ultimately impede the progress of, the animal rights movement.
The pro-vivisection lobby tries to focus the attention on a few isolated cases in their effort to make people forget the mass slaughter happening in laboratories.
There is already legislation in place that prohibits harassment and intimidation, so we are very concerned that these extra proposals could limit the right to freedom of expression in a peaceful and non-violent way and impinge on people's democratic right to protest.
It is often argued by pro-vivisectionists that we have the strictest laws in the world to protect laboratory animals.
In fact, a number of other countries also make this claim. The Home Office is very proud of its control, but whenever we go undercover we always discover numerous breaches of the law.