British lawmakers must decide on Friday whether to support assisted dying, following what is likely to be a heated debate inside parliament and protests for and against outside.

Were parliament to back the bill, and see it through the full legislative process, Britain would follow other countries such as Australia, Canada and some U.S. states in launching what would be one of its biggest social reforms in a generation.

The "Terminally Ill Adults (End of Life)" bill would allow mentally competent, terminally ill adults in England and Wales assessed by doctors to have six months or less left to live, the right to choose to end their lives with medical help.

The debate started in the House of Commons, the lower house of parliament, at 0930 GMT.

Those in favour of the bill argue it is about shortening the death of those who are terminally ill and giving them more control. Opponents believe vulnerable, ill people will feel they should end their lives for fear of being a burden to their families and society, rather than for their own wellbeing.

What is set to be a passionate debate could help sway the many lawmakers who have said they are yet to make up their minds in the free vote, when politicians vote according to their conscience rather than along party lines.

Supporters and opponents of assisted dying demonstrated outside parliament, reflecting the strength of feeling over a subject which has split the country nearly a decade after the last attempt to change the law was voted down.

"This is not about killing off people who are not wanted in society," said Emma Hobbs, 54, a former nurse who was holding photographs of her father. She said he had died in agony.

"It's about letting your loved ones have their own wish."

NATIONAL DEBATE

The proposal has stirred a national debate in Britain, with former prime ministers, faith leaders, medics, judges, the disabled and ministers in Prime Minister Keir Starmer's government weighing in on the subject.

One demonstration outside parliament on Friday morning held up banners saying: "Don't make doctors killers." Large adverts in the nearby Westminster transport station state: "My dying wish is my family won't see me suffer. And I won't have to."

Polls suggest that a majority of Britons back assisted dying and Labour lawmaker Kim Leadbeater, who proposed the bill, says the law needs to catch up with public opinion. She says the bill includes "the strictest safeguards anywhere in the world".

But support in parliament appears less secure, with some lawmakers saying the current proposal lacks detail and needs to be underpinned by more research to study the legal and financial implications of a change to the law.

Critics say that safeguards introduced around assisted dying have later been eased, for instance in Canada, where the legalisation initially for terminally ill patients was expanded to those with incurable conditions.

An attempt by a small number of lawmakers to derail the bill with a so-called "wrecking" amendment failed when the speaker of parliament's lower house declined to select it. The amendment had proposed halting the bill on the grounds there had not been enough time to consider the issue properly.

If lawmakers vote in favour of the bill, it will proceed to the next stage of the parliamentary process and face further votes in 2025.

Opponents could also attempt to "talk out" the bill so the debate ends without a vote.

Starmer has supported assisted dying in the past. He will vote on Friday but has not said how. His Labour Party, which has a large majority in parliament, is split over the matter.