UK lawmakers on Friday approved a bill to allow terminally ill adults in England and Wales to choose to end their lives in a historic vote in Parliament that takes it a step nearer to becoming law.

Members of Parliament voted 314-291 to back the Terminally Ill Adults (End of Life) Bill following an impassioned and respectful debate. The majority of 23 was less than the 55 when they last voted on the issue in November, meaning that some lawmakers changed their minds in the intervening months.

Since November, the bill has been scrutinized, leading to some changes in the proposed legislation, which has been shepherded through Parliament by Labour lawmaker Kim Leadbeater rather than the government.

"I appreciate it's a huge moment for the country," she told Sky News after the vote. "It was a huge sense of relief because this is the right thing to do." It's not quite law yet as the bill now goes to the unelected House of Lords, which can amend or delay policy, though it can't overrule the lower chamber.

The vote is potentially the biggest change to social policy since abortion was partially legalized in 1967.

The bill would allow terminally ill adults over the age of 18 in England and Wales, who are deemed to have less than six months to live, to apply for an assisted death. This particular bill doesn't apply to Northern Ireland and Scotland, the latter of which is holding its own vote on the issue.

Perhaps the most important change to the bill from last November was the dropping of the requirement that a judge sign off on any decision. Many in the legal profession had objected.