Sir Keir Starmer has said he is “committed” to allowing a vote on legalising assisted dying in the next Parliament.
The Labour leader made the pledge to campaigner Dame Esther Rantzen, whose revelation that she had joined the Dignitas assisted dying clinic in Switzerland has put the subject under the spotlight in recent months.
The Childline founder and broadcaster, 83, has urged politicians to grapple with the issue for the first time since 2015.
“I’m personally in favour of changing the law”, he said.
“I think we need to make time. We will make the commitment. Esther, I can give you that commitment right now.”
Asked whether he would like a vote within five years after the general election, the Labour leader told ITV: “Oh yes, definitely.
Dame Esther, who has stage four cancer, has been campaigning on the issue, including backing the launch of a petition demanding a parliamentary vote, which amassed tens of thousands of signatures over a few weeks.
Sir Keir supported a change in the law the last time the issue was voted on in the Commons nine years ago.
The Labour leader said in December that a private members’ bill and a free vote “seems appropriate”.
Polling suggests his Labour Party is on course to win the election expected later this year.
Sir Keir acknowledged “safeguards with teeth” would have to be put in place to protect the vulnerable.
Pressed on how he would calm critics’ concerns that vulnerable people could be pressured into assisted deaths, he said: “Firstly, I think the debate has to be conducted with respect.
“I personally think the law should be changed. There will be people equally passionate, with powerful points to make about why it shouldn’t be.”
He said: “When I consulted on this for the prosecutor’s guidelines, the churches and faith groups and others were very, very powerful in the arguments they made.
“We have to respect that and find the right balance in the end.
“I do think most people coalesce around the idea that there is a case (for assisted dying) where it is obviously compassionate, it is the settled intent of the individual, and there are safeguards with teeth to protect the vulnerable.”
Assisted suicide is banned in England, Wales and Northern Ireland, with a maximum prison sentence of 14 years.
In Scotland, it is not a specific criminal offence but assisting the death of someone can leave a person open to murder or other charges.
A Bill to make assisted dying legal in Scotland being put forward by Liberal Democrat MSP Liam McArthur is expected to come before Holyrood in the coming weeks.
It said legalisation in at least one jurisdiction was looking “increasingly likely” and suggested the Government must be “actively involved” in discussions about how to approach differences in the law.
The select committee’s report did not make a recommendation for a vote on the issue.
Downing Street said it would be up to Parliament whether or not to debate legalising assisted dying.
A No 10 spokeswoman said Prime Minister Rishi Sunak “has been moved by some of the experiences that have been shared by people and families in this situation”.
Sarah Wootton, chief executive of Dignity in Dying, said Sir Keir’s vow to Dame Esther sends “an important signal to all MPs and candidates: listen to dying people, listen to constituents, it’s time for change.
“Only a free vote early in the next parliament can deliver what our terminally ill citizens need – a safe and compassionate law providing choice at the end of life.”
Dr Gordon Macdonald, chief executive of Care Not Killing, said: “Changing the law to legalise assisted suicide and euthanasia in the UK would represent a dramatic change in how doctors and nurses treat and care for people and put the lives of the vulnerable, terminally ill and disabled people at risk.
“Indeed, these dangers are particularly acute when the health service is crumbling, hospices are underfunded and one in every four people who would benefit from palliative [care] can’t access it.”
He added: “Sir Keir needs to recognise the real dangers associated with legalising state-sanctioned killing, such as the pressure it puts on people to end their lives prematurely, and the growing body of evidence showing assisted suicide appears [to] normalise suicide in the general populations.”