The Archbishop of Canterbury has vowed he will never allow Church of England buildings to be used for gay weddings.
Dr Rowan Williams told MPs that he would not bow to pressure to enable his churches to be used for same-sex unions.
His intervention comes as the Coalition consults on plans to allow civil partnerships between gays and lesbians to take place in religious settings for the first time.
No church, mosque or synagogue will be forced to host the ceremonies – but some religious people are worried they could be open to discrimination suits if they do not open their doors to gay unions.
Some within the CofE have been calling on the Archbishop to move with the times and allow his churches to host gay weddings – pointing out that polls have shown that some two thirds of the British public would be in support.
But now Dr Williams, who was seen as a liberal when he took up his post, has indicated that on this issue he will ally himself with conservatives in the Church.
He told MPs that the CofE believed marriage could only be a union between a man and a woman – and that he would not be changing course.
The meeting was set up by Tony Baldry, Tory MP for North Oxfordshire, in order to build relations between the church and politicians.
Challenged by Simon Kirby, the Tory MP for Brighton Kemptown, to explain what he would say to a same-sex couple wanting a church union, Dr Williams said he would not countenance weakening its teaching on marriage, and would not be dictated to by the Coalition.
Mr Kirby said the comments would alienate gay Christians and would make the Anglican Church look out of touch.
‘I had hoped he might be more measured in his response and reflect on the cases for both sides of the argument more evenly, but he was very one-sided,’ he said.
‘Public opinion is moving faster than the Church on this issue and it is increasingly in danger of getting left behind.’
A consultation on allowing gays and lesbians to have civil partnership ceremonies in church will begin in April. It could even lead to gays getting full marriage rights.
Giles Fraser, canon chancellor at St Paul’s cathedral, said the Church of England should be embracing gay equality in marriages.
‘Gay relationships are perfectly capable of reflecting the love of God,’ he said.
‘Which is why the church should respond more imaginatively to the idea of same-sex blessings being celebrated in church.’
A spokesman for Lambeth Palace, the seat of the Archbishop of Canterbury, said: ‘The Church still believes on the basis of Bible and tradition that marriage is between a man and a woman and does not accept that this needs to change.
‘Civil partnerships now provide legal securities for same-sex couples but this does not, in itself, alter what we believe to be unique about marriage.’
Canon Glyn Webster, a senior member of the General Synod, said: ‘It’s only possible for a marriage to be between a man and a woman. I’m not saying there can’t be loving relationships between people of the same sex, but that doesn’t equate to marriage.
‘I want the Church to keep to the policy of refusing to hold blessing services for same-sex couples.’