Britain has proposed jail sentences of up to five years for animal rights protesters who obstruct experiments.
The measures seek to protect all firms associated with animal experimentation - from suppliers such as building contractors to couriers and cleaners - by outlawing attacks at any point along the supply chain.
"The simple fact is that attacks by animal rights extremists put medical breakthroughs in areas like AIDS, cancer and Alzheimer's directly at risk," said Trade and Industry Secretary Ms Patricia Hewitt in a statement.
The measures follow proposals announced in November to stop animal rights campaigners targeting scientists by strengthening police powers to direct protesters away from people's houses.
Researchers welcomed the move but animal rights campaigners said new bans would push activists towards extreme measures.
Activists say animals are often mutilated or poisoned unnecessarily in tests to develop new medicines; the government says animals are only used in vital research where no alternative is available.
The British government claims activists drive investment away from Britain, threatening a fast-growing bioscience sector worth more than £3 billion sterling a year.
Scientists, pharmaceutical companies and contract research laboratories have been the target of protests such as hate mail, hoax bombs and even the fire-bombing of scientists' cars.
Institutions like the country's oldest drug-testing firm, Huntingdon Life Sciences, have long complained of harassment.