The UK’s two longest-serving MPs have united to oppose the assisted dying bill, which is due to be debated in Parliament next week.

In a joint article for the Guardian, Labour’s Diane Abbott and the Conservative Sir Edward Leigh have said their politics “could not be more different”.

However, they say they share concerns that the proposed legislation would put “vulnerable minorities” at risk.

They also argue that the process for bringing the bill to Parliament has been “rushed” and that scrutiny of its contents “is being limited”.

The bill has been proposed by backbench Labour MP Kim Leadbeater, who argued it would help stop people experiencing “very harrowing” deaths.

She also said it contained the “strictest safeguards anywhere in the world”.

The bill – named the Terminally Ill Adults (End of Life) Bill – would give someone expected to die within six months the right to choose to end their own life.

The legislation would require two independent doctors and a judge to determine whether the person satisfies the criteria to take their own life – including expressing a clear wish to do so, free from coercion.

Expressing their fears about the bill, Abbott and Sir Edward said: “Evidence from elsewhere suggests those most at risk when assisted suicide is legalised are vulnerable minorities.

“Such people, unlike privileged elites who are used to exercising autonomy over every part of their lives and who can afford good-quality social and palliative care, are most likely to resign themselves to an assisted death against their will because they are unable to access the support they require.

“Imagine the pensioner whose children cannot afford houses of their own watching her limited savings, earmarked for those children, disappearing on social care and so feeling a ‘duty to die’.

“Or consider the elderly widow who has been hospitalised and worries she is taking up a valuable bed in an NHS under significant strain and would be better off dead.”

They acknowledged such incidents would be “relatively rare” but said it would be “simply not possible to avoid such scenarios if assisted suicide were to be made legal”.

As the longest-serving female and male MPs in Parliament, Abbott and Sir Edward hold the titles of Mother and Father of the House.

The two MPs – who between them have nearly 80 years of parliamentary experience – also objected to the timetable for debating the bill.

They noted that in 2015, the last time a similar bill was introduced, MPs had seven weeks to read the bill before debating it in the House of Commons, whereas Leadbeater’s bill had been published just 18 days ahead of the first debate.

“The inadequacy of this timescale is heightened by the unprecedented number of new MPs,” they said.

“Parliament will have sat for just 12 weeks by the time MPs vote on what is, quite literally, a matter of life and death.”

“Many MPs are still relatively unfamiliar with normal parliamentary procedure, let alone for private members’ bills, of which this will be the first in this Parliament.”

Private members’ bills are pieces of legislation proposed by backbenchers, rather than the government.

Following debate of the bill, MPs will get a free vote, meaning they will not have to follow any party line.

If the bill passes its first vote, it will received further scrutiny from MPs and peers.

In order to become law it would need approval from both the House of Commons and House of Lords.

Earlier this week, former Labour deputy leader Harriet Harman insisted the bill would get “as many days as necessary”.

She said the “only time constraint” was that, in order to pass, the bill needed to complete all its stages by November 2025.

“I don’t think the government is showing any signs of wanting to restrict debate.”