MPs are continuing their debate on assisted dying laws today after doctors and psychiatrists expressed concern over a lack of safeguards in the proposed legislation.
The Terminally Ill Adults (End of Life) Bill is undergoing a second day of report stage in the House of Commons, with various amendments likely to be voted on.
The Bill's third reading - when MPs will decide whether to approve or reject the overall Bill - could take place next Friday.
It passed its second reading stage following an historic Commons vote in November, when MPs supported the principle of assisted dying by a majority of 55.
But, since then, a number of MPs have switched their stance on the Bill.
According to campaigners, 18 MPs who either supported the Bill's second reading or abstained at November's vote have now moved towards opposing it, while three MPs have switched the other way.
The Bill aims to allow terminally ill adults in England and Wales - with less than six months to live - to legally end their lives.
Earlier this week, more than 1,000 doctors wrote to MPs to demand they vote against the 'unsafe' legislation.
The Terminally Ill Adults (End of Life) Bill is being spearheaded by Labour MP Kim Leadbeater
They expressed concerns that the Bill will 'widen inequalities' and 'provide inadequate safeguards'.
The proposed legislation 'does not protect against the risk of coercion, particularly for women and the elderly', the letter added.
The Royal College of Physicians (RCP) and Royal College of Psychiatrists (RCPsych) have also expressed concerns.
RCP said there was not yet 'adequate protection of patients and professionals' in the Bill, while RCPsych said there were 'too many unanswered questions about the safeguarding of people with mental illness'.
But some MPs who are doctors are among the Bill's strongest supporters.
Meanwhile, seven RCPsych members - including a former president and vice president - have written to MPs to distance themselves from their college's concern.
They instead described the current Bill as 'workable, safe and compassionate' with a 'clear and transparent legal framework'.
Among the issues being debated by MPs on Friday are a ban on advertising assisted dying, and the regulation of substances to be used by a terminally ill person to bring about their death.
Labour MP Kim Leadbeater, who is spearheading the Bill, has previously said it 'would feel inappropriate' for assisted dying 'to be something which was advertised'.
But Bill opponent Labour MP Paul Waugh warned of 'unspecified exceptions, which could make the ban itself worthless'.
He added that he had put forward a tighter amendment to 'strengthen the Bill on this issue and to better protect the vulnerable'.
Ms Leadbeater said other possible amendments include ensuring 'any approved substance used for assisted dying is subject to robust regulation and scrutiny', which she said is 'essential for clinical safety, public confidence and ethical integrity'.
As it stands, the proposed legislation would allow terminally ill adults to apply for an assisted death, subject to approval by two doctors and a panel featuring a social worker, senior legal figure and psychiatrist.
MPs are entitled to have a free vote on the Bill and any amendments, meaning they vote according to their conscience rather than along party lines.