British prime minister Tony Blair has condemned the "appalling" activities of anti-vivisection extremists and re-affirmed the British overnment's support for animal testing.
Writing in the Sunday Telegraph, the Prime Minister pledged to do all that was necessary to root out the criminal minority behind the campaign of terror.
Mr Blair said his government would also consult on plans to keep shareholders' names secret to protect medical research which has saved hundreds of millions of lives.
The proposal comes after extremists threatened shareholders in drugs company GlaxoSmithKline they would have their names published on the internet unless they dumped their shares.
The Prime Minister's intervention also follows the imprisonment on Thursday of four people who ran a six-year hate campaign against the owners of a guinea pig farm, culminating in the theft of a pensioner's body from her grave.
Mr Blair wrote: "The appalling details of the campaign of intimidation - which include grave robbing - show the depths to which the animal extremists are prepared to stoop.
"The letter writing campaign just launched against GlaxoSmithKline shareholders shows why we must step up efforts to support and protect individuals and companies engaged in life-saving medical research."
The Prime Minister said that the planned Company Law Reform Bill would allow directors to keep their home addresses private to protect them from intimidation.
Companies would also be able to refuse to release the names of shareholders unless requested for "a proper purpose".
He added that the government was considering going even further, with some companies allowed to keep shareholders' lists entirely secret.
"We will also consult further on exempting companies from providing full public details of shareholders in future," he wrote.
"If more measures are needed to protect individuals, universities and firms or to root out the criminal extremist fringe, we will provide them."
Mr Blair said that British scientists and companies were in the forefront of medical research and made a "huge contribution to human health and well-being", while creating thousands of highly-skilled jobs.
Mr Blair also said that he intends, in a rare move for any minister, to sign the People's Petition in support of animal testing in the UK.
With almost 14,000 signatures so far, it describes itself as "giving a voice to the silent majority" of people in favour of properly-regulated medical research.
"Announcing that I am to add my name to the online petition in support of animal testing when necessary is something of a break with tradition - and a sign of just how important I believe it is that as many people as possible stand up against the tiny group of extremists threatening medical research and advances in this country," he wrote.