LONDON — A proposed bill to allow terminally ill adults in England and Wales to choose to end their lives is set to fall Friday as parliamentary time runs out, nearly a year since elected members of parliaments gave their backing.

Though the Terminally Ill Adults (End of Life) Bill was passed by the House of Commons last June, the U.K.’s revising chamber, the House of Lords, has effectively talked it out since then.

Proponents of what has been termed “ assisted dying ” — sometimes referred to as “assisted suicide” — hoped it would mark the biggest change to social policy in the U.K. since abortion was partially legalized in 1967.

But opponents in the House of Lords have managed to hold up its passing by filing more than 1,200 amendments to the bill. That is believed to be a record high number for a piece of legislation that was tabled by a backbencher rather than by the government. Bills proposed by backbenchers can only be debated on a Friday, limiting the time available.

With the current session coming to an end next week, the bill will fail. Each five-year parliamentary term is subdivided into a number of sessions of the government’s calling, and bills can only become law if they are discussed and voted on within a single session.

Campaigners for assisted dying have expressed their anger at the sight of unelected politicians holding up the will of the elected chamber. They have insisted that they intend to bring the bill back in the next parliamentary session, which begins after King Charles III outlines the government’s upcoming program in a speech to both houses of Parliament on May 13.

The sponsor of the bill in the House of Lords, Charlie Falconer, said he felt “despondent” that a piece of legislation, which he said was “so important to so many, has not failed on its merits, but failed as a result of procedural wrangling.”

He said many terminally ill people and their relatives “have shown such courage and forbearance” and have been “utterly bewildered by the way we have behaved.”

The bill that’s been making its way through parliament over the past 18 months or so had proposed allowing adults in England and Wales, with fewer than six months to live, to apply for an assisted death subject to the approval of two doctors and an expert panel.

Those tabling amendments in the House of Lords said they have been providing necessary scrutiny to strengthen the legislation. Some have branded it unsafe and unworkable, citing their concerns around potential coercion of vulnerable people and a lack of safeguards for those with disabilities.

Kim Leadbeater, who introduced the Bill to the House of Commons in late 2024, has said she will “keep pushing for a safer, more compassionate law until Parliament reaches a final decision.”

Last month, lawmakers in the Scottish Parliament rejected legislation that would have made Scotland the first part of the United Kingdom to allow terminally ill adults to end their lives. Scotland has a semiautonomous government that has authority over many areas of policy, including health.

Assisted suicide — where patients take a lethal drink prescribed by a doctor — is legal in countries including Australia, Belgium, Canada, Luxembourg, the Netherlands, New Zealand, Portugal, Spain, Switzerland and parts of the U.S., with regulations on qualifying criteria varying by jurisdiction.