LONDON (Reuters):

Faced with a bid from Canadian clerics to bless gay weddings, the worldwide Anglican Communion now faces a real risk of breaking apart over differences between its liberal and conservative wings.

"The train and the buffers are getting closer," said religious journalist and commentator Clifford Longley.

"The Anglican Church is unravelling," Longley concluded as Archbishop of Canterbury Rowan Williams struggled to keep his global flock of 77 million Anglicans together in a bitter war of words over homosexuality.

The latest challenge to Williams, spiritual head of the Anglican Church, came from Ottawa.

The local branch of the Anglican church in the Canadian capital asked Ottawa Bishop John Chapman to authorise the blessing of homosexual marriages.

Chapman is an advocate of such blessings and if he approves the request it is likely to enrage the 'Global South' - conservative churches in Africa, Latin America and Asia - and increase the chances of a worldwide split.

Sharp contrast

American liberals sparked the row by ordaining openly gay Gene Robinson as bishop of New Hampshire in 2003.

In sharp contrast to the regimented hierarchy of the larger Roman Catholic Church, the Anglican communion is largely run by broad consensus.

But Williams faces a pivotal decision on which primates he invites to next year's Lambeth conference, the 10-yearly gathering of Anglican leaders.

"When preparing that guest list, he is acting as the Anglican Pope. He has the list, he has that pencil," Longley said. "It all turns on whether Gene Robinson is invited to Lambeth."

Archbishop of York John Sentamu, one of Williams' closest allies, has already warned Anglican conservatives that boycotting the church summit means they would effectively be expelling themselves from the worldwide communion.

The Episcopal Church, its 2.4 million-member U.S. branch, has already splintered over the issue with a growing number of conservative U.S. clerics pledging allegiance to African bishops who take a tough line against homosexuality.

Katharine Jefferts Schori, head of the Episcopal Church, made it clear again Monday that the U.S. church will not back down.