Supporters of bill to legalise assisted dying for terminally ill people say they will try again to pass legislation.

A UK bill to legalise assisted dying in England and Wales will not become law after efforts by unelected lawmakers to stall its passage through Parliament.

Time ran out for the Terminally Ill Adults (End of Life) Bill on Friday after hitting a parliamentary quagmire of more than 1,200 bill amendments tabled by appointed lawmakers in the House of Lords.

The bill, which proposed legalising euthanasia for adults with less than six months to live who had clearly expressed a wish to die, was passed by lawmakers in the House of Commons last June.

Both chambers of the United Kingdom Parliament must approve legislation for it to become law. Bills that are still in progress when a session ends usually fail. Under parliamentary rules on bills proposed by backbenchers, the legislation could only be debated on Fridays, thus limiting its chances of passing.

More than 200 lawmakers signed a letter late Thursday blaming the bill’s scuppering on “deliberate delaying tactics pursued by a minority of peers opposed to its passage”.

Lord Charlie Falconer, who sponsored the legislation in the upper chamber, accused opponents of “pure obstructionism”. “It was an absolute travesty of our processes, which a few Lords manipulated by putting down 1,200 amendments … and then talking and talking and talking,” he said.

Campaigners opposed to changing the law expressed relief. “It is now clear that this bill was both unsafe and unworkable,” said Gordon Macdonald from the Care Not Killing campaign group, who said the Lords had exposed the bill as “skeleton legislation” that was “riddled with gaping holes”.

A spokesperson for the Christian Medical Fellowship (CMF), which represents medical professionals opposed to assisted dying, said, “It is not possible to construct an assisted suicide service that is safe, equitable, and resistant to placing unacceptable pressure on the most vulnerable.”

But those in favour of the bill pledged to fight on.

“We’re incredibly angry with what’s happened, but we’re determined to get it through. This is not the end, we will not be stopped,” said campaigner Rebecca Wilcox, whose mother has a terminal diagnosis. She expressed hope that a lawmaker will carry on the fight when parliament reconvenes in mid-May for its next term.

Kim Leadbeater, the MP who introduced the bill in the House of Commons in 2024, said supportive lawmakers would “go again” in the next parliamentary session, though a different MP will likely need to introduce a new bill.

“The issue is not going away — there’s a very clear direction of travel around the world,” she said, adding polling in the UK showed support for the change.

Lawmakers in the self-governing British dependencies of Jersey and the Isle of Man have already approved euthanasia legislation, but the moves are still awaiting royal assent.

Lawmakers in Edinburgh in March rejected a bill in the devolved Scottish parliament to legalise assisted dying.