A move to legalise assisted dying could be delayed so much by Lords who oppose the change that it is timed out of becoming law, sources have said.

In historic scenes in the House of Commons on Friday, members voted in favour of passing a bill that would make assisted dying legal in some circumstances – despite the majority support halving to just 23 MPs.

The Terminally Ill Adults (End of Life) Bill will now head to the Lords, where it is understood peers against legalising assisted dying are poised to add hundreds of amendments so it runs out of Parliamentary time.

Peers against the law change feel emboldened to scupper the legislation – even though it was supported by MPs – due to the fact it is not a government bill or linked to a Budget and was not in the Labour Party election manifesto.

An opposition campaign source told The i Paper: “We’re still going to be looking to fight this and to stop it from becoming law […] think we’ve got an opportunity to do that.”

They said the fact the majority support for the Bill had fallen from 55 to 23 “reflects a lot of the issues” with it, adding that “a lot of peers” have concerns about protections for vulnerable people.

If the bill does not become law within this Parliamentary session it will have to be reintroduced and begin the entire process again as it is a Private Members Bill. How long a session lasts is up to the government, however, and this Parliamentary session could last for several months.

“It would not be unreasonable of them to say that it wasn’t in any party’s manifesto, it was passed with a very narrow majority and it’s not a money bill,” the source said.

“I think that they would be completely within their rights to do everything they can in the House of Lords to try and defeat it and to try and make it so it doesn’t become law.”

Lords warned against ‘playing games’

Labour MP Kim Leadbeater, who introduced the Private Member’s Bill in the Commons, cautioned against the Lords “playing games” with it.

Asked if she expected any tactics such as a delay to the bill or a wrecking amendment, Leadbeater replied: “I really hope that there are no funny games because the process has been extremely thorough.”

“I would be upset to think that anybody was playing games with such an important and such an emotional issue,” she added.

But Tory peer Lord Jackson, who is opposed, told The i Paper peers would “seek to very, very heavily amend it”, which will make it hard to pass in time. 

He said he suspected there was a majority against it in the Lords but added that it was hard to predict due to an influx of new peers in recent months.

“I think there’s a number of people in the Lords that will make the case quite vigorously that it was not properly scrutinised. There wasn’t sufficient time to consider all the amendments made,” he said.

“People will seek to very, very heavily amend it […] and therefore it’ll be quite a difficult passage,” he added. “Given that the Government’s got a very large number of bills still to get through the Lords, is it going to extend a lot of political capital on a bill that has split its own party in the Commons?”

Religious peers publicly criticised the bill after MPs voted it through, warning that palliative care is not up to an acceptable standard and indicating they would heavily oppose it in the Lords.

Bishop of London Dame Sarah Mullally, a former chief nursing officer for England, said instead work is needed to better fund access to “desperately needed palliative care services”.

Catholic Church archbishop John Sherrington said Bishops of England and Wales have been consistently outspoken in their opposition.

“Genuine compassion involves accompanying those who need care, especially during sickness, disability and old age,” he said.