David Cameron said the introduction of same sex marriage was one of his proudest moments as Prime Minister, having worried and "wobbled" over the issue in the face of some heated opposition within the Conservative Party.
In his autobiography, Mr Cameron says he does, however, regret abstaining from voting on a motion put by Tory colleague Iain Duncan Smith to block gay couples' right to adopt children, rather than voting against it.
"Equal marriage was one of the most contentious, hard-fought and divisive issues during my time as prime minister," Mr Cameron writes in an excerpt from his book, For The Record, published in The Times newspaper.
"We would lose party members; one even came to my surgery and tore up their membership card in front of me. It was an issue that I would worry and even wobble over. But I have absolutely no regrets, and it is one of the things of which I'm proudest."
One of Mr Cameron's most memorable moments around the issue came when a male Downing Street staffer had told him: "It's because of you that I'm able to marry my boyfriend this weekend."
"It was a reminder that politics has the power to make a difference and change people's lives," Mr Cameron wrote.
The former PM said he had had to approach the subject carefully at a Tory conference to ultimately gain the required support within "a party that carried so much baggage" on the matter.
"The way to do it, I decided, was not to talk about what a departure it was," he wrote, "It was to talk about how the reform was rooted in our fundamental beliefs: 'Conservatives believe in the ties that bind us; that society is stronger when we make vows to each other and support each other. So I don't support gay marriage despite being a Conservative, I support gay marriage because I am a Conservative.'
"Applause rang out. That short sentence was a giant leap for our Party."
Mr Cameron still laments, however, his inaction over an ultimately unsuccessful bid to prevent gay people from adopting.
"I also ended up abstaining on - rather than voting against - Iain Duncan Smith's rejection of gay couples' right to adopt," he said. "I should have proactively supported that right."
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