A bill to legalise gay marriage in Britain passed a crucial hurdle in parliament on Tuesday, despite efforts by lawmakers from Prime Minister David Cameron's Conservative party to wreck the plans.
Members of the House of Commons voted by 366 to 161 in favour of the same sex marriage bill, a majority of 205, and it will now go to the unelected House of Lords for consideration.
There was applause as the result was read out, although the bill is likely to face stiff opposition when it is debated in the Lords next month, especially from the bishops.
The vote followed a marathon debate on Monday in which Cameron was forced to make a deal with the opposition Labour party to defeat a bid by his own rebellious Conservative MPs to scupper the bill.
Right-wing Tories had proposed an amendment to allow heterosexual couples to form civil partnerships, which was condemned by Cameron's office as a "wrecking amendment" that would have delayed the introduction of the new law.
Although the motion was easily defeated with Labour's help, the depth of the Conservatives' divisions were made clear when it was revealed that 128 of its MPs had voted against the bill, 11 more than voted in favour.
Britain has seen none of the mass protests over gay marriage held across the channel in France, which last weekend became the 14th country in the world to legalise it.
However, police said they had detained a woman after she tried to drive through the main gates of parliament shortly after the vote, but did not directly link the two events.
Some 54 percent of Britons are in favour of allowing same-sex couples to marry, according to a YouGov poll for the Sunday Times.
But lawmakers are sharply divided, and Conservative former minister Norman Tebbit stoked the row on Tuesday by claiming gay marriage could result in a lesbian queen giving birth to an heir by artificial insemination.
"When we have a queen who is a lesbian and she marries another lady and then decides she would like to have a child and someone donates sperm and she gives birth to a child, is that child heir to the throne?" he told The Big Issue magazine.
The rancour over gay marriage within the Conservatives has heaped further pressure on Cameron, who is already facing bitter opposition from many Tories over his leadership style and a promised referendum on Britain's EU membership.
The prime minister was forced to send a mass email to Conservative activists after an unnamed ally was reported to have called them "mad, swivel-eyed loons".
"I am proud of what you do. And I would never have around me those who sneered or thought otherwise," he wrote.
The "loons" comment fuelled accusations that Cameron is out of touch with traditional Tories and that the prime minister surrounds himself with people from his own privileged background.
Party co-chairman Lord Andrew Feldman, who strongly denies rumours he was behind the comment, was a schoolmate of Cameron's at the elite Eton College.
Many Conservative supporters fear that with a general election two years away, Cameron's backing for gay marriage is driving traditional Tory voters to the UK Independence Party (UKIP).
The anti-immigration, anti-EU party is a fast-rising force in British politics and made strong gains in local elections last month.
A new poll suggested that support for the Conservatives has slumped to 24 percent -- just two percent ahead of UKIP -- although a different poll put the Tories on 31 percent.
Cameron's promise to hold a referendum on Britain's membership of the European Union after the next election and by 2017 was intended to mitigate the impact of UKIP.
But last week, more than 100 Tory MPs took the unprecedented step of backing a motion expressing regret that the government's legislative plans for the year contained no guarantee of such a vote.