Hindus, Baha'is and secularists are still represented but the Church of England, Salvation Army, Methodist Church and Roman Catholic Church have all left, jeopardising its future.

Peter Vlachos, the National Secular Society delegate, said he was appalled and accused the church groups of "abusing" the forum.

He said: "Rather than supporting and championing equality and human rights, the Churches have tried to use the consultative process to try to gain further exemptions from equalities legislation. They wanted the freedom to discriminate and they didn't get it so now they've walked away."

He claimed that correspondence sent to the society showed that the churches had hoped to turn the religion and belief consultation into an "interfaith forum" where the non-religious would be excluded.

The collapse of the Equality Commission's Religion and Belief Consultative Group comes as traditionalist Christians today petitioned the Equalities Minister Harriet Harman to intervene in the Equality Bill which tonight completed its passage through the Lords and now returns to the Commons. The traditionalists want to prevent a change in the law that will allow civil partnership ceremonies to take place in religious buildings.

Although the change is "permissive" which means no cleric could be prosecuted for refusing to carry out a gay "marriage", bishops and other clergy fear that any who refuse could risk prosecution under European human rights legislation.

The Pope recently intervened in the debate over equality legislation in Britain. Benedict XVI is expected to use his visit to Britain in September to preach moral virtue.

Leaders across the churches continue to defend the right of Christians and other religions to discriminate against women, gays and others according to their religious beliefs.

The Religion and Belief Consultative Group was set up in 2004 as a reference group for the religion and belief representatives on the Steering Group for the Equality and Human Rights Commission.

Although the group advised the Equality and Human Rights Commission, it received no government funding and all attendance was voluntary.

The Church of England's representative on the group, Dr Malcolm Brown, the church's director of mission and public affairs, told The Times: "Problems began when the Religion and Belief Consultative Group moved from being a discussion group about the forthcoming equalities legislation to being a group with which the Equalities and Human Rights Commission consulted on a semi-formal basis.

"Although religion and belief form a single strand in equalities legislation, they are not represented by a single set of interests. The British Humanist Association and the National Secular Society use the group to argue for the exclusion of religious voices from public life.

"Despite the most careful chairing, every meeting has degenerated into an impasse between the secular and the religious voices. The group is not fit for purpose as a consultative body.

"The Church of England remains completely committed to dialogue and cooperation with the other world faiths and the structures which enable those conversations. Our withdrawal, along with the other major Christian denominations, from the group does not affect that commitment at all and we will continue working with the other faith groups on the equality agenda and in relating to the EHRC.

But the EHRC needs to find ways to consult with all its stakeholders without assuming that we can sit around a table with those whose objective is to remove us from that table."

In a joint letter sent to the group's chairman Barney Leith, of the Baha'i faith, the Christian members said the meetings had not been achieving "all that had been hoped". They admitted that the group's members are "incapable of reconciliation" and that its consultative role had been "disappointing".

Keith Porteous-Wood and Terry Sanderson of the National Secular Society, which represented atheists, accused the Christians of leaving because they were "not getting their way". The secularists have accused the church groups of attempting to use the group to lobby for the right to continue to discriminate according to religious doctrine in areas such as education, employment and gay adoption.

The Reverend Peter Colwell, of Churches Together in Britain and Ireland, said the group was unable to deliver and the churches wanted to engage "more constructively" with the Equality and Human Rights Commission. "The hope is that this will precipitate the folding up of the group."

A spokesman for the Commission said the group was set up to provide a joint framework for faith communities and non-religious belief organisations to keep in touch with developments."Unfortunately, it has become clear that some Christian church members of the group felt unable to continue in the group in its current form," he added.

END