Westcountry MPs have spoken in support of same-sex marriage legislation as the proposals cleared their first hurdle in the Commons.
.But the Conservative Party appeared riven, despite David Cameron's personal backing, as the House backed the proposals by a large margin of 400 to 175.
With Labour and Liberal Democrats strongly in favour, early indications suggested that 139 Tories had voted against the Bill and 132 in favour, with dozens more not voting.
It appears Mr Cameron is struggling to get the majority of his party to back same-sex couples getting married in both civil and religious ceremonies, where a religious institution has formally consented.
The result followed more than six hours of stormy debate on the Marriage (Same Sex Couples) Bill, with opponents claiming the plans would undermine the institution of marriage and that marriage can only be between a man and a woman.
But Stephen Gilbert, Liberal Democrat MP for St Austell and Newquay, who gave one of the most praised speeches, said the "historic legislation" will end discrimination and send a signal that the Government "values everybody equally in this country".
He told MPs: "I am a gay man who grew up in a rural part of our country, in Cornwall, in a working class background.
"I grew up 20 years ago in an environment that made it hugely difficult for me to be open, honest and upfront with my family, with my friends, with my workmates about the choices I wanted to make in life and the people I wanted to see.
"That was unacceptable 20 years ago and it is unacceptable today but for many hundreds of thousands of people it remains the case today."
Labour MP for Exeter Ben Bradshaw – a committed Christian and the first MP to enter a same-sex civil partnership in 2007 – said: "I entirely support the Government's decision to make this a permissive law, allowing those religions and denominations that wish to celebrate the loving same-sex relationships of their members to do so."
He went on that the opposition of religious institutions, including the Church of England, also to civil partnerships "leads me to conclude only that their objection to the Bill is not about the institution of marriage or even the word, but about a residual prejudice against same-sex relationships".
Totnes, Devon Conservative MP Sarah Wollaston said the legislation would help sweep away prejudice, saying: "Within my postbag I have received hateful correspondence, suggesting treatment for homosexuality. But I can tell that person homosexuality needs no treatment. Our sexuality is fundamental to who we are." She called on MPs to "vote for love and equality".
Ahead of the vote, Mr Cameron said allowing gay people to marry will "make our society stronger".
In a last-minute televised statement recorded in 10 Downing Street, he insisted he had always been "vocal" in his support for the move.
"I am a strong believer in marriage. It helps people commit to each other and I think it is right that gay people should be able to get married too," he said.