In an historic vote, MPs have approved a bill which would pave the way for huge social change by giving terminally ill adults in England and Wales the right to end their own lives.

The Terminally Ill Adults Bill, which was backed by 314 votes to 291, will now go to the House of Lords for further scrutiny.

The bill was approved with a majority of 23 MPs, representing a drop from the first time it was debated in November, when it passed by a margin of 55.

The vote came after an emotionally-charged debate which saw MPs recount personal stories of seeing friends and relatives die.

It is likely, although not guaranteed, that the House of Lords will approve the bill later this year.

If that happens, ministers would have a maximum of four years to implement the measures, meaning it could be 2029 before assisted dying becomes available.

MPs were allowed a free vote on the bill, meaning they did not have to follow a party policy.

Prime Minister Sir Keir Starmer backed the measure, while Conservative leader Kemi Badenoch and Health Secretary Wes Streeting voted against.

Labour MP Kim Leadbeater has shepherded the bill through the Commons and speaking to the BBC after the vote she said she was “over the moon”.

“I know what this means for terminally ill people and their loved ones.”

She added it had been a “particularly emotional week” because it marked nine years since the murder of her sister Jo Cox, who had been a Labour MP at the time.

“Jo used to say if good people don’t step forward and come into politics then what do we end up with?

“And even though some of us feel quite out of place in this place at times we are here to make a difference and we’re here to make positive change that society has asked us to do.”

Critics have argued the bill risks people being coerced into seeking an assisted death but Leadbeater said she was “100% confident” sufficient safeguards were in place.

Conservative MP Danny Kruger, who has been a prominent opponent of the bill, said the majority had been cut in half adding: “It is clear support for this bill is ebbing away fast.”

He said he hoped the House of Lords would either reject the proposed legislation or “substantially strengthen it”.

He argued it would not be unconstitutional for peers to block a bill approved by the democratically-elected House of Commons, pointing out that the proposal had not appeared in Labour’s election manifesto.

However, supporters of the bill have said that they are confident that, although the Lords are likely to amend the bill, it will not be rejected outright.

Any changes made in the House of Lords would have to be approved by MPs, before the bill could become law.

Dame Esther Rantzen, a broadcaster and prominent supporter of the bill, said: “This will make a huge positive difference, protecting millions of terminally ill patients and their families from the agony and loss of dignity created by a bad death.

“Thank you, Parliament.”

On the other side, Baroness and former Paralympian Tanni Grey-Thompson said she had heard from “disabled people [who] are absolutely terrified” about the bill.

Grey-Thompson, who will get a vote on the bill in the Lords, said she would put forward amendments to make it “as tight as possible” to ensure people could not be coerced.

Jan Noble, head of the hospice charity St Christopher’s, said it was now “vital” the government ensured “high-quality end of life care was available for everyone”.

“For that we need a better funding model for hospices,” she said.

Hundreds of campaigners gathered outside Parliament in the blazing heat to make sure their voices were heard as MPs made up their minds.

Those in favour of the bill had united under the Dignity in Dying campaign, wearing flamingo pink t-shirts, and there were smiles and tears as they shared hugs following the vote.

Pamela Fisher, a lay preacher from the Church of England who supports assisted dying, welcomed the narrow vote in favour, saying she believed the vote was “a major step forward to the creation of a more compassionate society”.

The family of Keith Fenton had been standing on Parliament Square with a placard of the former Squadron Major in his Royal Engineers regalia all morning and were “absolutely delighted” with the result.

Earlier, his widow Sara had explained she told Keith she didn’t want him to go to a Dignitas clinic in Switzerland when he became very ill with Huntington’s disease – but realised she was “being selfish” after Keith tried to take his life.

Reflecting the split among MPs on this issue of conscience, there were also large numbers of people campaigning against the Bill, many with concerns over how to protect vulnerable people.

Sister Doreen Cunningham had been sitting by Westminster Abbey alongside other nuns from the Sisters of Nazareth mission, and said she hoped the Lords would be able to introduce stronger safeguards.

“The MPs did talk about safeguards but they’re far from what we would call safeguards,” she added, as fellow disappointed campaigners consoled themselves by singing quiet hymns.

George Fielding from the secular Not Dead Yet campaign said the vote was “incredibly disappointing” as he believes it will “endanger, foreshorten and I would say kill the most vulnerable people in our society”.

As someone with cerebral palsy, he believes the bill is “ableist” and many of those who end their own lives when they become disabled are experiencing “unprocessed hurt and trauma”.

Sitting by a mock graveside in his wheelchair, George said: “We must ask the Lords to scrutinise this bill line by line to promote other alternatives – palliative care, social care, a better benefits system — to ensure everyone has the right to live a joyful life.”

Before the vote, the House of Commons spent more than three hours debating the general principles of the bill.

Conservative MP James Cleverly said he was struck by the number of medical professional bodies who were neutral on the principle of assisted dying but were opposed to the specific measures in the bill.

“When the people upon whom we rely to deliver this say we are not ready… we should listen,” he said.

Speaking in favour, Labour MP Peter Prinsley said: “There is an absolute sanctity of human life, but we are not dealing with life or death – we are dealing with death or death.

“For there is also a sanctity of human dignity and fundamental to that is surely choice – who are we to deny that to the dying?”

At the start of the day, MPs voted on a series of amendments that had been debated last week.

These included a measure to close the so-called “anorexia loophole” which would stop people qualifying for assisted dying on the basis of life-threatening malnutrition.

MPs backed that amendment as well as one requiring the government to publish a review of palliative care services within a year of the bill passing.

An attempt to block access to assisted dying for people suffering mental health problems or because they feel “burdensome” was defeated by a majority of 53.