'I'm emotionally ruined' Concern for the vulnerable drives unlikely alliances as MPs face historic vote

When Kim Leadbeater came top of the ballot of the private members' bills, she did not immediately decide to attempt a generational change in the way the British state handles the end of life. But, she says, it was an opportunity that rarely comes for a backbench MP.

- Jessica Elgot

The past few months of campaigning for her bill to legalise assisted dying has exhausted her. It has been a licence for everyone she meets to tell harrowing stories. "I'm emotionally ruined," she said in her Commons office, among piles of folders containing photos of people who have told her stories of their suffering. "I cannot walk down the street without someone stopping me and telling me the story about someone who's died."

Her decision to bring the bill has meant a record number of new MPs will today be faced with a conscience issue that could define this parliament. Terminally ill people and their families will gather outside parliament to make their final pleas to MPs to vote this through. It would be an emotional moment for even the hardest Commons veteran. But because of the numbers, it will be the new intake who are the deciding voice.

The debate has become increasingly bitter, especially after calls from the health secretary, Wes Streeting, to vote down the bill on the grounds of the state of the NHS, an intervention which infuriated one side but struck a chord with many who were conflicted.

MPs on either side have made unlikely alliances - Conservative cabinet veterans alongside new Labour MPs who just deposed their Tory colleagues. Evangelical Christians have found themselves organising in their offices alongside atheist trade unionists.

Leadbeater heard from a number of other causes that lobbied for her attention in the fortnight it took for her to reach her decision on the bill. It would be wrong to say she was not influenced by Keir Starmer's decision to promise Esther Rantzen that a vote would be held, but Leadbeater says she was motivated primarily by the personal stories she heard.

There was no approach from Starmer personally. But when Leadbeater decided she would take up the cause, there was a private approach to Downing Street to see if there were objections - and there were none.