UK Prime Minister Tony Blair has taken a stand against animal rights extremists by pledging to sign an online petition to express his support for necessary animal testing of drugs, but inevitably drew swift criticism for his actions.

The PM said he would sign the People’s Petition – already backed by more than 16,000 signatures since being drawn up by the Coalition for Medical Progress last month – shortly after investors in GlaxoSmithKline were sent threatening letters by an unidentified animal rights group.

The CMP comprises representatives of drug companies, national research councils, doctors groups and medical charities.

Writing in UK newspaper The Sunday Telegraph, Blair said: “Many millions ... will be spared an early death or a life of pain because of the research now underway. They deserve our support. And they should get it.”

He said it is important that “as many people as possible stand up against the tiny group of extremists threatening medical research and advances in this country.”

Crucially, in light of the GSK development, Blair said companies with links to animal testing may be allowed to keep the identities of their shareholders secret. This is already a feature of the government’s new Company Law Reform Bill, but the provision could be taken further, he said.

Welcoming the PM’s support, GSK chief executive Jean-Pierre Garnier said: "I am greatly encouraged by his personal commitment, and that of his government, to ensuring an environment in the UK that is conducive to the research and development of vital new medicines."

But the British Union for the Abolition of Vivisection (BUAV), while saying it is important to take a tough line on extremism, criticised Blair for his ‘blind support’ of animal testing, claiming it “shows that he is failing to grasp the difference between condemning extremism and supporting an outmoded, immoral and unproductive scientific technique.”

The Association of the British Pharmaceutical Industry also applauded the PM’s courage in taking a strong position on the issue, and welcomed statements by several major investment companies, made in a letter to the Financial Times, expressing their determination to maintain shareholdings in companies that are "legitimately engaged in lawful research to the benefit of society.”