Britain proposed new laws on Tuesday to stop increasingly militant animal rights campaigners from harassing scientists involved in medical experiments.

 Determined to tackle what has long been a highly emotive issue for animal-loving Britons, the government promised legislation in coming months to stop activists targeting scientists at their homes.

"The bill will introduce new measures to deal with harassment by animal rights extremists," Queen Elizabeth told parliament, reading the government's legislative program.

Included in a new Serious Organized Crime and Police Bill, the measures would:

-- strengthen police powers to direct protesters away from people's homes, including bans of up to three months.

-- create a new offence of demonstrations outside homes "in such a way that causes harassment, alarm or distress to residents."

-- strengthen individuals' protection by widening the scope of the 1997 Protection from Harassment Act.

Scientists in Britain say they face the worst animal rights extremism in the world. Some government ministers have called it a form of terrorism.

A planned research laboratory at Oxford University has been subjected to protests, some of them violent, and a project to build a Cambridge primate laboratory had to be scrapped.

Last week Swiss health care group Novartis AG became the latest firm to say rights campaigners might force it to rethink investments in Britain.

Other scientists working at institutions such as Britain's oldest drug-testing firm, Huntingdon Life Sciences, have long complained they are targeted physically and verbally by militants who oppose their work.

Some scientists' cars have been fire-bombed.

While the government argues animals are only used in vital research where no alternative is available, rights activists say cruel practices are widespread and unnecessary.

The Association of the British Pharmaceutical Industry (ABPI) welcomed the proposals.

"(They) are vital if we wish to see the continued development of new medicines in Britain," said the ABPI's director general Dr Richard Barker.

"The campaign of harassment, intimidation and violence that the lunatic fringes of the animal rights lobby have inflicted on those working on medicines research has included hundreds of instances of people being targeted in their own homes.

"Already, some companies are talking of moving their work to other countries, which would be a disaster for Britain."