The result of the vote on gay marriage was read out to a packed House of Commons
Party leaders at Westminster have hailed the significance of the backing for same-sex marriage in England and Wales in a key Commons vote.
Prime Minister David Cameron said Tuesday's vote had been "an important step forward" and Labour leader Ed Miliband called it a "proud day".
MPs voted in favour of the Marriage (Same Sex Couples) Bill by 400 to 175, a majority of 225.
But 136 Tory MPs opposed the bill and have continued to voice their concerns.
MPs were given a free vote on the bill, meaning they were not ordered to vote a particular way by party whips.
Their decision to back the bill at second reading signifies that they approve of it in principle. The legislation will now receive more detailed parliamentary scrutiny.
If it becomes law, the bill will enable same-sex couples, who are currently able to engage in civil partnerships, to get married in both civil and religious ceremonies - the latter only with the consent of religious institutions.
'Lords opposition'Voting lists show that 136 Conservatives - almost half of the party's MPs - opposed the bill.
This figure included two cabinet ministers - Environment Secretary Owen Paterson and Welsh Secretary David Jones - eight junior ministers, and eight whips.
Of the remaining Conservative MPs, 127 were in favour, 35 did not vote, and five registered an abstention by voting both in favour and against.
Opening the debate, Equalities Minister Maria Miller urged MPs to back the bill
Among those who voted against, Conservative MP David Burrowes predicted that the legislation would receive substantial opposition when it arrived in the House of Lords.
However, he said the vote had shown that the party was in touch with the country: "The nation is divided, we have shown ourselves as a party to be divided."
Former Tory defence minister Sir Gerald Howarth said that the government had no mandate for such a "massive social and cultural change", which had not been mentioned in the 2010 Conservative manifesto.
Meanwhile, Conservative MP Sir Roger Gale said he hoped the the prime minister would make changes to the legislation.
''It is clear that there are a huge number of people who are very concerned indeed,'' he said.
He had told the Commons debate: "It is not possible to redefine marriage. Marriage is the union between a man and a woman, has been historically, remains so."
'Equality landmark'Mr Miliband, the leader of the opposition, welcomed the outcome of the Commons vote.
"This is a proud day and an important step forward in the fight for equality in Britain," he said.
Conservative MP Sir Roger Gale: ''There are a huge number of people who are very concerned indeed''
"The overwhelming majority of Labour MPs supported this change to make sure marriage reflects the value we place on long-term, loving relationships whoever you love.
"Equal marriage builds on Labour's successes in government which include the repeal of Section 28, equalising the age of consent, the introduction of civil partnerships and changes to the rules governing adoption."
Deputy Prime Minister and Liberal Democrat leader Nick Clegg said he believed people would look back at the vote and see it as "a landmark for equality in Britain".
He said: "No matter who you are and who you love, we are all equal. Marriage is about love and commitment, and it should no longer be denied to people just because they are gay.
"The Liberal Democrats have long fought for equal marriage. It is party policy and I am proud that the Liberal Democrats are part of the coalition government that are making it happen."
Four of the 56 Liberal Democrat MPs opposed the legislation.
They included former coalition minister Sarah Teather who, in a statement, expressed concern that the definition of marriage was being changed, which could make family life more unstable.
"It is my view that where the extra protections offered to same-sex couples are marginal, and where the potential negatives to society over a period of time may be more considerable, I am unable to support the bill," she said.
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