The assisted dying bill is set to be published next week amid widespread disquiet from MPs about scrutiny of the legislation, which its proponents believe is pushing people towards the no campaign. The Labour MP Kim Leadbeater, who is helming the private member’s bill, has promised colleagues they will see the detail of the legislation by early next week ahead of the vote on 29 November. Some MPs said they believed the original plan had been to publish the bill just a week before the vote. A major cross-party push is under way on both sides of the issue to win over a significant number of undecided MPs across all parties – though Tory backers of the law change believe the key to potential victory is a significant number of Conservatives who have changed their mind on assisted dying since the 2015 vote, where the measure was comprehensively defeated. MPs will have a free vote, meaning they can vote according to their conscience, on the bill, which is expected to make provisions for terminally ill people, with less than six months to live, to end their life at a time of their choosing, subject to safeguards. Leadbeater is being aided by the former Conservative cabinet minister Kit Malthouse and the senior Lib Dem Christine Jardine. But there is gathering momentum from the opposition, with organisers including the Conservative MP Dr Ben Spencer, the Lib Dem MP Munira Wilson and the former shadow cabinet minister Rachael Maskell. The proposal has a number of passionate supporters among the new intake of Labour MPs, including Jake Richards, who had intended to propose it as a private member’s bill himself though it was adopted by Leadbeater, who had higher priority in the ballot. “We’re confident in the numbers of the new Labour MPs that the majority will support,” one backer said. But other MPs said that there were still a very high number of undecideds – as many as 100 Labour MPs – and that many were moving towards potentially abstaining. A significant number of MPs say they plan to hold local public assemblies for constituents to give their views. Some of the measure’s backers believe there are concerns that could be addressed once the legislation is published. “A lot of people are undecided,” one Labour MP who is backing the law change said. “People are still worried about the detail. It has to be watertight, clean and simple. I would not support something that was extended to intolerable suffering – because I think it’s too hard to define in law. “It’s essential the patient is interviewed on their own, away from family. It’s essential doctors have the right to decline to sign the paperwork. It’s essential that no healthcare or social worker is permitted to mention assisted death as an option – it must be of the patient’s asking.” The decision of the health secretary, Wes Streeting, to say he will not back the legislation is also playing on the minds of some MPs – though others have been critical of his decision to intervene. Starmer has been publicly in favour of the law change but the cabinet secretary, Simon Case, has warned cabinet ministers not to get involved in the fray. “I presume they thought, given Keir said he was in favour, he would make this happen – which tells you something about his actual control over Labour party,” said one MP who was in favour of the change. “This is the first conscience issue new MPs have faced and it’s very difficult. A lot think it’s unfair this has happened to them so soon. And particularly Right to Life – which also do anti-abortion stuff – they bombard the inbox. Progressive liberals are hopeless at organising “The tactic is basically to generate doubt amongst progressives so they don’t show up. You may find a lot of abstentions on the 29th.” The majority of Liberal Democrat MPs are thought to be in favour of the change, according to party sources, though the party leader, Ed Davey, has said he has reservations. The Reform UK chair and MP Richard Tice has also expressed support for the change.