Religious figures who support gay marriage will today launch a fightback against church leaders who have come out against same-sex marriage.
Representatives from the Church of England, liberal Jews, the Quakers and the Unitarian and Free Church will join forces at Westminster to declare their backing for the Government's plans to legalise civil gay marriage, which have provoked strong opposition from leaders of the Anglican and Catholic churches.
Some faiths want the Coalition to go further by giving churches the freedom to carry out religious same-sex marriage.
Those attending the conference will include Giles Fraser, a priest who resigned as Canon Chancellor of St Paul's Cathedral last autumn following the Occupy protests; Dr Jeffrey John, the Dean of St Albans; Paul Parker, Recording Clerk for the Quakers; Rabbi Roderick Young; Derek McAuley, chief officer of the General Assembly of Unitarian and Free Christian Churches; and the Rev Sharon Ferguson, chief executive of the Lesbian and Gay Christian Movement.
Mr Parker said the Quakers believe that all committed relationships are of equal worth.
"The new proposals allow civil partnerships in Quaker meeting houses, but that is not a marriage; it is a legal contract, not a spiritual one," he said. "We don't seek to impose this on anyone else. For Quakers this is an issue of religious freedom."
Rabbi Young, who will represent the Movement for Reform Judaism at the conference, said: "The proposal to extend civil marriage to gays and lesbians is greatly to be applauded. However it is not enough. It is a bizarre situation when lesbian and gay rabbis may perform a legal religious marriage for heterosexual couples, but are denied the right to experience that joy for themselves with their partners."
Today's meeting has been organised by Labour, which backs David Cameron and Nick Clegg in their efforts to bring in gay marriage, despite vocal opposition from many Conservative MPs. Labour also wants the Government to give churches the freedom to carry out religious same-sex marriages – without forcing them to do so by law.
Yvette Cooper, the shadow Home Secretary, said last night: "Many religious organisations and people within different faiths support same-sex marriage.
"Whilst opposition from some church leaders has been strong, other prominent church figures are supporting same-sex marriage. It should be recognised that there are many views within and between different faiths. If you believe in religious freedom, those organisations that do want to offer same-sex marriage ceremonies should be allowed to do so."
She said Mr Cameron must not be deterred by opposition within his own party and beyond and urged him to call an early debate in Parliament rather than stall on the issue.
The Government is expected to reject the calls to allow churches to "opt in" to religious same-sex marriage, a proposal which could fuel the Conservative revolt on the issue.
But church leaders fear the planned civil marriage law would spark legal challenges in the European Court of Human Rights by gay rights campaigners, which would force churches to conduct religious same-sex marriage against their will.