The government is treating the Bill as a conscience issue, meaning MPs will have a free vote rather than being whipped to follow a party line, making the outcome of the vote difficult to predict.
Prime minister Sir Keir Starmer has previously supported assisted dying but has not said how he will vote on Friday.
He has asked his Cabinet not to campaign in the debate, but several ministers have spoken out, including the health secretary Wes Streeting, who is against it.
There have also been a series of high profile interventions, with three former Conservative prime ministers telling the Telegraph, external they oppose the plans, which would legalise assisted dying in England and Wales.
Liz Truss said “the judicial system should be protecting lives, not ending them” and “vulnerable people would be put under appalling pressure to end their lives early”.
The understands Baroness Theresa May and Boris Johnson are also against the proposed legislation, which would allow terminally ill adults expected to die within six months to seek help to end their own life.
Supporters of the bill argue it has strict safeguards to prevent coercion and would give people a choice over how they die to avoid unnecessary suffering.
The three former prime ministers are no longer MPs so will not get a vote this week. However, Baroness May is a member of the House of Lords so she would get an opportunity to vote on the bill if it is approved by MPs and progresses to the second chamber.
It comes after former Labour Prime Minister Gordon Brown also declared his opposition to the legislation last week, saying the death of his daughter convinced him of the “imperative of good end-of-life care”.
Instead he called for a commission to look at how to improve palliative care.
End of life care was also raised at Prime Minister’s Questions by Liberal Democrat leader Sir Ed Davey, who called on Sir Keir Starmer to protect funding for hospice services, raising the case of a constituent, Christine, whose father who lost out on palliative care due to funding cuts.
Davey said: “He died a few weeks later in excruciating pain – Christine said it was terrible to watch him suffer.”
The PM responded that the government was putting in place a 10 year plan to fix the NHS, and pointed to the Terminally Ill (End of Life) Bill debate on Friday.
He said: “Whichever way that vote goes, we must invest properly in care across our health service… to make sure the NHS can give the care that everybody would expect across the spectrum, including end of life care.”
