David Cameron has said the church must "wake up" to the case for equality, as he promised to face down Tory critics and introduce same sex-marriage before the next election.
"It’s something I feel passionately about and I think if it’s good enough for straight people like me, it’s good enough for everybody and that’s why we should have gay marriage and we will legislate for it," he said.
The prime minister was speaking at a reception for Lesbian, Gay, Bisexual and Transgender (LGBT) reception at Downing Street last night.
Cameron admitted that the Conservative Party had for many years "got itself on the wrong side" on the issue of gay rights and had locked people out who were naturally Conservative from supporting it
"I think I can make that point to the Church," he said."Gently".
"Of course this is very, very complicated and difficult issue for all the different Churches," he said.
"But I passionately believe that all institutions need to wake up to the case for equality, and the Church shouldn’t be locking out people who are gay, or are bisexual or are transgender from being full members of that Church, because many people with deeply held Christian views, are also gay.
"And just as the Conservative Party, as an institution, made a mistake in locking people out so I think the Churches can be in danger of doing the same thing."
The prime minister's comments came the day before the SNP government in Scotland decided to legalise gay marriage, after ministers finally agreed the framework for legislation.
The coalition government in Westminster has pledged to bring in a similar law for the rest of the UK before 2015.
However Cameron faces stiff opposition from some Tory backbenchers as well as some religious leaders who are opposed to the plans.
The prime minister told the reception last night that the government would not back down from promoting equal rights.
"The promise I can make you is that this coalition government is committed to both changing the law and also working to help change the culture and the Conservative party absolutely backs that.
He added: "This is something I personally feel very passionately about.”
Cameron said he was "absolutely determined" that the coalition government will follow in the tradition of gay rights legislation introduced by Tony Blair, including the equalisation of the age of consent and the introduction of civil partnerships, by legislating for gay marriage in this parliament.
"I make that point not only as someone who believes in equality but as someone who believes passionately in marriage," he said.