By the narrowest of margins, this Friday could usher in the largest societal shift to hit Britain in fifty years. According to the Daily Dazzling Dawn, the historic vote among MPs over the legalization of assisted dying seems to be close to a tie, with proponents of the practice reportedly holding a slim lead.If passed, it could lead to the most significant reform in British society since the abolition of the death penalty in 1965 and the introduction of abortion two years later.

Labour backbencher Kim Leadbeater has insisted her Terminally Ill Adults (End of Life) Bill is “robust”, with potentially the “strictest protections” against coercion anywhere in the world, requiring sign-off by two doctors and a High Court judge before a person was permitted to end their life.She has the support of the former prime minister David Cameron as well as two former health secretaries, Andy Burnham and Matt Hancock.

But high-profile opponents include former Conservative prime ministers Theresa May, Boris Johnson and Liz Truss, and former Labour PM Gordon Brown, who last week said that the death of his newborn daughter in January 2002 had convinced him of the “value and imperative of good end-of-life care”.At the 11th hour, MPs were also warned by a regulator that parliament should be given more assurances that the bill is compatible with human rights.

The Equality and Human Rights Commission, which says it holds a neutral position on assisted dying, warned that there had been “insufficiently detailed analysis” of human rights considerations.A leading consultant also told that coercion by doctors and other medical professionals poses one of the biggest dangers to vulnerable, elderly and disabled people if assisted dying becomes legal.Ilora Finlay, who is a consultant in palliative care as well as a member of the House of Lords, said that “it is often almost impossible” to detect when patients are subjected to coercion.

It is understood that at least 175 MPs have asked to speak during a five-and-a-half-hour debate on the bill, which is scheduled to begin on Friday at 9.30am – but the majority have not yet declared publicly which way they will vote.

However, according to a spreadsheet belonging to one of the campaigns and seen by The Independent, the two camps are neck and neck, with 199 for to 196 against out of a total of 650.

If the bill does pass by a small margin, it could draw comparison with Britain’s decision to leave the European Union in 2016 – a vote that was won by 52 to 48 per cent.

Sir Keir Starmer’s government is split on the issue of assisted dying, with MPs being given a free vote. Sir Keir has chosen not to reveal how he will vote. Speaking on Thursday, he said: “Obviously the government is neutral on this, and it is a genuinely free vote for all members of parliament, and I don’t want to put pressure on them.

“I’ve obviously got a huge amount of interest and experience in this, having looked at every single case for five years that was ever investigated.”

But the health secretary, Wes Streeting, has been vocal in his opposition, as has the justice secretary Shabana Mahmood.As well as Ms Mahmood and Mr Streeting, education secretary Bridget Phillipson and business secretary Jonathan Reynolds have said they will vote against the legislation.

The culture secretary Lisa Nandy, work and pensions secretary Liz Kendall, Northern Ireland secretary Hilary Benn, transport secretary Louise Haigh, and energy secretary Ed Miliband have all said they will back it.

The bill, which covers England and Wales, states that only terminally ill adults with less than six months left to live and a settled wish to die would be eligible to be helped to die.

If it passes its first parliamentary stage on Friday, civil servants and ministers will begin work on it.

MPs would be able to vote twice more on the bill, including on any amendments, and again at its third and final Commons reading, after which it would go to the House of Lords. If passed by the Lords, the bill would then gain Royal Assent, bringing it into law.