A GWENT MP said he made a “decision based on his conscience” when he voted against gay marriage.

Paul Murphy was one of only two Gwent MPs in the House of Commons who declined to back a change in lawthat extends marriage to same-sex couples.

The Torfaen MP, who is also a papal knight, said people have sent him messages of support despite some hostility towards his move on social media.

Last week’s vote exposed divisions within the Conservative parliamentary party, with one Welsh political commentator reflecting speculation that the measure was an attempt to isolate traditionalists in the organisation.

Under a bill proposed by the UK government couples of the same sex will be able to get married.

Churches will need to “opt in” to hold ceremonies, and the Church of England and Church in Wales would be banned from offering them.

An overwhelming majority of MPs approved the bill at its second reading – 400 to 175 – with 136 Tory MPs voting against. All eight Welsh Conservatives were among them.

The bill will now be subject to more parliamentary scrutiny and is set to go to the House of Lords, where there is speculation that more than half of Conservative peers will vote against.

Mr Murphy was one of two Welsh Labour MPs to vote against the move – but was on the receiving end of some criticism on the social networking site Twitter.

He said: “People have the right to voice their opinions if they disagree with me – it’s a free country.

“Others have chosen to send messages of support. This was a free vote, so I made an honest decision based on my conscience.

“I was proud to be a member of a Labour government which established civil partnerships and abolished section 28. On this occasion, though, I felt that as a Christian I needed to reflect my genuine concerns about redefining marriage.

“Now it’s time to move on and talk about the big issues like jobs and the economy.”

Without a manifesto commitment from either of the UK coalition partners, and opposition from within Tory ranks, the move by David Cameron’s government sparked questions as to why the UK government ploughed ahead.

Political commentator and managing director of public affairs agency Positif Daran Hill said: “It has been well documented the PM has been dogged by Eurosceptics and the party’s old guard in allowing the Conservatives to diverge and modernise from its traditional roots.

“Some commentators have questioned whether driving the vote was a measure to further isolate the party traditionalists and allow them to ‘out themselves’ as political dinosaurs. The vote also came at a time when Cameron needed a significant popularity boost.”

However, he said, the “less cynical side of him” wanted to see it as a move to modernise the UK and allowgay couples to be on an equal footing with heterosexual couples.

Apart from David Davies, who voted against the bill together with his other Welsh Tory colleagues, the rest of Gwent’s MPs voted for the change in the law.

Labour’s Chris Evans, MP for Islwyn, said the move created a huge amount of debate among his constituents, with his post bag split in half.

He said: “I have always been clear that I am a supporter of same-sex marriage as long as no church or religious organisation will be forced to conduct these ceremonies if they did not want to.”

Jessica Morden, Labour MP for Newport East, said she thought it was the right thing to do.

“The legislation doesn’t force anybody to do anything,” she said, “but it does mean that churches that would like to marry gay couples are able to.

“I certainly have had emails from gay couples in the last week saying thanks for voting the way you did.”

Ms Morden said she thought most people believe it was a reasonable thing to do. “Obviously there are some strong opinions.

We’ve got to respect that. But I think the legislation bent backwards to allay people’s fears.”

Andrew White, director of gay rights group Stonewall Cymru, said he believed MPs had reflected the popular mood.

He said: “We are absolutely delighted that MPs have shown such an overwhelming majority and that they are in touch with 21st-century Wales.”