David Cameron says a Commons vote in favour of legalising gay marriage in England and Wales is an important step forward.
But it could be a step back for the Tory party after the issue split its MPs with 127 in favour and 136 against. Support from Labour and the Lib Dems meant the proposals where backed by a majority of 225.
Conservative MP David Burrowes is a Christian and has been leading the debate against same-sex marriage.
He told Premier's Victoria Laurence on the News Hour he's faced severe hostility for not supporting the bill but is remaining steadfast:
The legislation would enable gay couples to get married in both civil and religious ceremonies, where a religious institution had formally consented.
Paul Parker, who's Recording Clerk for the Quakers in Britain, tells Premier why they've been supporters of gay marriage since 2009:
However, the National Church Leaders Forum that represents African and Caribbean churches in the UK, says gay marriage is "not ordained of God" and a "threat to the human race".
Bishop Eric Brown believes Civil Partnerships provide gay couples with enough equality. Bishop Brown told Premier's Marcus Jones on the News Hour he doesn't buy into the idea that the legislation brings about fairness.
Culture Secretary Maria Miller's behind the move, and said it makes sense: "The depth of feeling, love and commitment is no different between same-sex couples than opposite sex couples. "This bill enables society to recognise that commitment in the same way too through marriage."
The government believes the wording of the bill will ensure the Church of England and the Church in Wales, both opposed to the law, will not face any legal challenges. All religious organisations will be able to opt-in to holding ceremonies - but the Church of England and the Church in Wales would first need to agree to change canon law. Despite this the Church of England sent a briefing note to MPs on the bill outlining why it can't support the proposed legislation.
It included the reasons why specific wording is needed to give the Church the same protection as other faith groups. The Bishop of Wakefield, the Rt Revd Stephen Platten, tells Premier gay couples should be taken seriously but he doesn't want the ceremonies to be called 'marriage'.
Liberal Democrat MP Stephen Gilbert said the publication of the government's bill represents a major moment for equality: "I know people are annoyed that we're legislating specifically against the Church of England marrying same-sex couples.
"Unfortunately, as long as they are the Established Church and have an obligation to marry anyone who wishes to be married in their church under current common law and canon law, we have to make sure that they are not forced to do so until they are ready to accept gay couples.
"That's a matter for the Synod and rightly, elected politicians have to stay out of their internal affairs – however frustrating that may be. If it were up to me, I'd disestablish the Church tomorrow but it isn't, so I can't."
The Catholic Church also opposes the law.
Archbishop Peter Smith said: "The Catholic Church continues to support marriage understood by society for centuries as the significant and unique lifelong commitment between a man and a woman for their mutual well-being and open to the procreation and education of children.
"Marriage is rooted in the complementarity of man and woman. For these reasons the Church opposes the Government's Bill to re-define marriage.
"Despite claims by supporters of the Bill that the central issue is one of equality, the Bill actually seeks to re-define marriage and will have consequences for society at large.
"It became clear during today's debate in the House of Commons that the government has not thought through a number of profound problems in the Bill raised by members of Parliament during the debate.
"It will be extremely important that the many concerns we and others have expressed will be fully and carefully considered during the next stages of the Bill's passage through Parliament."
MPs had a free vote on the issue, meaning they were not be ordered to vote for or against by party whips.
Veteran Tory MP Sir Peter Bottomley sits on the House of Commons Ecclesiastical Committee - he told Premier's News Hour why he supports gay marriage:
The Equality and Human Rights Commission issued an analysis to MPs of the bill in light of the requirements of the Equality Act 2010 and the Human Rights Act 1998.
The EHRC believes that churches and individual ministers will not find themselves forced by litigation to conduct same- sex marriages and no one will be required to promote views about same-sex marriage which they do not support. It also concludes that the bill is in accordance with the European Court of Human Rights' interpretation of human rights legislation and would therefore withstand any challenge in the court.
Helen Grant is an equality minister and tells Premier the legislation is in line with her Christian values of equality.
Coalition for Marriage is delighted by the scale of the Parliamentary opposition to ill-thought through and divisive gay marriage bill
Its Campaign Director Colin Hart said: "The scale of the opposition against the Government's profoundly undemocratic plans is astonishing, and sends a clear message to the Prime Minister that he faces a lengthy and damaging battle to redefine marriage.
"Just a few months ago, if we had predicted this result, no one would have believed us, but our clear and simple message that these proposals are undemocratic and will lead to all sorts of unintended consequences has struck a chord with ordinary voters and now scores of MPs.
"We have consistently warned the legislation contains no safeguards for those who work in the public sector.
"Top lawyers, with a track record of winning against the Government, have said the quadruple lock is not sustainable and instead of trying to answer these questions the PM remains hell bent on ramming this bill through Parliament in a dangerously short period of time.
"Mr Cameron hopes that this matter is now settled. He is wrong. His attempts to distract those in his own party and the wider country from the fall out will fail.
"More importantly this is not the end of the fight against these ill-thought through and divisive plans.
"There are more votes in the Commons, more speeches, potentially dozens of amendments and then the bill will go to the Lords where the voting arithmetic is very different."