Assisted dying will not become law in England and Wales after proposed legislation branded “hopelessly flawed” by opponents ran out of time amid claims of a “denial of democracy” from supporters.

The Terminally Ill Adults (End of Life) Bill, which had been making its way through parliament for the past year and a half, fell on Friday with peers speaking passionately on both sides of the argument.

While the bill had successfully passed two votes in the House of Commons, albeit with a narrower majority on the second occasion, it did not face a vote in the Lords.

It instead ran out of time, with Charlie Falconer, who had steered it through the upper chamber, saying 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”.

The bill 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.

More than 1,200 amendments to the bill had been suggested in the Lords, with more than 800 of those tabled or sponsored by seven peers.

Lord Falconer described the process of the bill as “horrible”, saying it had not failed to finish its journey through the Lords due to a lack of time, but rather “because a small minority were not willing to cooperate, as we normally do, to ensure that there can be proportionate debate”.

A Tory former minister and peer, Kenneth Baker, accused opponents of the bill of a “prolonged filibuster”, branding the situation a “denial of democracy”.

Tanni Grey-Thompson, a Paralympian peer who had spoken out against the bill, said it had failed because “there are too many gaps in it” adding she felt there was “a lot of misunderstanding about what people might get” under a law change.

Those opposed to the bill had branded it “unsafe and unworkable” and “bad law”, citing their concerns around potential coercion of vulnerable people and a lack of safeguards for those with disabilities.

Jane Campbell, a former commissioner at the Equality and Human Rights Commission, told fellow peers that disabled people had contacted her to say this “particular bill frightens them, and they want me to explain to your lordships why it is dangerous”.

The crossbench peer, who has spinal muscular atrophy, addressed the chamber remotely to say disabled people “fear unequal access to care shaping their choices, they fear subtle coercion that cannot be easily detected”.

Therese Coffey, a Conservative former deputy prime minister, told the debate she feared “that many peers and many MPs are putting choice for some ahead of concern on coercion for others”.

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

Supporters have vowed to try to bring the bill back in parliament’s next session, with its sponsor in the Commons, Kim Leadbeater, who watched proceedings from the gallery on Friday, saying she would again enter her name in the ballot of private member’s bills.

As the draft legislation fell, Leadbetter stood and held her hand to her mouth, shaking her head. Campaigners have said they could use the Parliament Act to get the bill through if it was selected.

A rarely used piece of legislation, the act allows for bills that have been backed by the Commons in two successive sessions but rejected by peers to pass into law without Lords approval.