LONDON (Reuters) -Britain's proposed assisted dying law for terminally ill people will be debated in parliament on Friday, when lawmakers consider changes to the legislation, ahead of the next vote on whether to proceed with the historic law or scrap it.

Lawmakers voted 330 to 275 in November in favour of allowing assisted dying, paving the way for Britain to follow other countries such as Australia, Canada and some U.S. states in what would be the biggest social reform in a generation.

The bill, under which mentally competent, terminally ill adults in England and Wales with six months or less to live would be given the right to end their lives with medical help, has since come under intense scrutiny and has already been significantly revised.

Lawmakers will get a final vote on the revised bill after what is likely to be a emotional debate given the sensitive subject matter. The high number of amendments -- there are dozens -- means the debate is likely to be continued next month.

Opinion polls show that a majority of Britons back assisted dying and supporters say the law needs to catch up with public opinion. But some lawmakers have raised concerns over the proposed legislation's protections for vulnerable people. Others have said palliative care needs to be improved first.

Both the Telegraph and Guardian newspapers reported that a growing number of lawmakers who had initially voted in favour of the bill are now planning to withdraw their support.

Prime Minister Keir Starmer's Labour government is neutral on the bill, meaning politicians can vote according to their conscience rather than along party lines.

The most significant change from the original bill is the removal of the need for court approval for an assisted death.

Instead, a panel made up of a senior legal figure, a psychiatrist and a social worker would decide if an applicant is terminally ill and has the capacity to make the decision to end their own life.

Any further amendments must be agreed separately by a vote. If Friday's session is deemed too short to consider the amendments, the legislation could return for further debate on June 13, before the crunch vote takes place.

If it passes that vote, the legislation will be sent to the House of Lords, parliament's upper chamber, for further scrutiny.

In 2015 British lawmakers rejected legalising assisted dying by a vote of 330 to 118.

The legislation under consideration does not apply to Northern Ireland or Scotland. The Scottish parliament voted on Tuesday in favour of a similar bill, sending it for further legislative scrutiny.

(Reporting by Sarah Young and William JamesEditing by Frances Kerry)