Conservative Anglican leaders are to stage a breakaway summit in Jerusalem that could irretrievably fracture the 400-year-old Church over a dispute with liberal clergy about homosexuality.

The timing could not be worse for Archbishop of Canterbury Dr Rowan Williams, who is struggling to maintain unity among the world's 77 million Anglicans over the issue.

The clergy, headed by Nigerian Archbishop Peter Akinola, are due to meet in Jerusalem six weeks before July's Lambeth Conference in Britain - the 10-yearly gathering of all Anglican leaders.

"It does look like a mess. It is another nail in poor old Rowan's cross," said religious commentator and broadcaster Clifford Longley.

"I do see it breaking up," he said, contemplating the future of a church which, unlike the regimented hierarchy of the Roman Catholic Church, is run by broad consensus with Dr Williams as first-among-equals.

The Anglican church has slid down the road to schism since 2003 when American liberals sparked the row by ordaining openly gay Gene Robinson as bishop of New Hampshire.

This enraged "The Global South" - conservative churches in Africa, Latin America and Asia - which account for more than half of the world's Anglican followers.

The leaders say the Global Anglican Future Conference (GAFCON) in Jerusalem will "provide opportunities for fellowship and care for those who have decided not to attend Lambeth".

GAFCON is being portrayed as "a pilgrimage back to the roots of the Church's faith".

But the decision has backfired in the Middle East, where Anglican leaders have called for the cancellation of the summit which they fear could exacerbate Christian-Muslim tensions.

Suheil Darwani, the Anglican Bishop in Jerusalem, said: "I am deeply troubled that this meeting, of which we had no prior knowledge, will import inter-Anglican conflict into our diocese."

"Indeed, it could further inflame tensions here. We do not want to see further dividing walls," he said in a statement.

Conservatives and liberals show no sign of backing down.

Bishop Katharine Jefferts Schori, leader of the Episcopal Church that says it has 2.4 million Anglican members in the United States, says her church has been unfairly singled out about consecrating gay bishops.

Jefferts Schori, head of the Anglican body in the United States, said New Hampshire's Gene Robinson "is certainly not alone in being a gay bishop, he is certainly not alone in being a gay-partnered bishop".

"He is alone in being the only gay-partnered bishop who is open about that status," she said.

Longley said: "The Liberals are not prepared to pay the price for unity, nor are the Conservatives."

"They have pushed the issue beyond the danger point."