The introduction of gay marriage in England and Wales moved closer tonight after legislation cleared a major hurdle in the House of Lords.
The Marriage (Same Sex Couples) Bill was given its second reading after a wrecking amendment was soundly defeated by 390 votes to 148.
The result came after a marathon and impassioned two-day debate involving more than 90 speakers, with Archbishop of Canterbury Justin Welby among those condemning the change.
However, the legislation faces further efforts to derail it as the Upper House begins detailed scrutiny.
MPs have already endorsed the Bill despite opposition from dozens of Tory backbenchers who have refused to follow David Cameron's lead on the issue.
The scale of the vote against independent crossbencher Lord Dear's amendment this evening was hailed by equal rights campaigners.
Lord Dear had branded the Bill "fatally flawed", arguing it would "completely alter the concept of marriage as we know it".
He urged peers to use their free vote to halt its progress and send ministers back to "the drawing board".
But Baroness Stowell of Beeston, for the Government, said the legislation was a "force for good" which would strengthen the institution of marriage.
In the closing moments of the long debate, Lady Stowell also held out an olive branch to religious leaders opposed to conducting same sex marriages.
If further changes to the legislation were necessary to make protections for religious organisations clearer, the Government would consider doing so, she said.
Stonewall chief executive Ben Summerskill said: "We're absolutely delighted.
"We always expected a tough challenge in the House of Lords, and Lord Dear's 'fatal motion' - very rarely used - demonstrates the lengths to which a minority of peers are, sadly, still prepared to go to deny full equality to lesbian, gay and bisexual people.
"In the last 24 hours alone, opponents of equality in the House of Lords have compared loving, committed relationships to incest and polygamy.
"Britain's 3.7 million gay people don't deserve to be second class citizens in their own country. A tough fight lies ahead and we'll continue to work tirelessly every single day to get equal marriage through the Lords."
But Colin Hart, campaign director for the Coalition for Marriage, said: "The Government may have won the vote today, but what was clear from the debate was the huge opposition to almost every part of the Bill.
"We will continue to campaign to save traditional marriage and today's vote and the concerns expressed by many peers mean we will be able to introduce safeguards that will protect teachers, registrars, chaplains and anyone who works in the public sector. And if the Government refuse to accept these changes, they risk losing the legislation at third reading."