Archbishop of York John Sentamu warned Anglican conservatives on Monday that boycotting a church summit next year means they will effectively expel themselves from the worldwide communion.

American liberals, who sparked the row in the first place by ordaining an openly gay bishop, have locked horns with conservatives from Africa and Asia who represent at least a third of the world's 77 million Anglicans.

Conservatives in the so-called "Global South" signalled after a meeting in London earlier this month that they were unlikely to attend next year's meeting of the Lambeth Conference, the 10-yearly gathering of Anglican leaders.

"It is impossible for us to see how, without discipline in the communion and without the reconciliation that we urge, we can participate in the proposed conference," they said.

That provoked a sharp response on Monday from Sentamu, one of the closest allies of Archbishop of Canterbury Rowan Williams, spiritual head of the Anglican church.

"Anglicanism has its roots through Canterbury," Sentamu told The Daily Telegraph.

He warned rebellious conservatives: "If you sever that link you are severing yourself from the communion. There is no doubt about it."

Sentamu, a former judge in Uganda who was forced to flee the Idi Amin regime, said: "I want to warn people -- don't spend the next century trying to find a way back."

"They would be the ones voting with their feet and saying, as far as we are concerned, we are the true Anglicans."

Drawing up the list of Lambeth attendees, Rowan Williams did not invite two American bishops, Gene Robinson and Martyn Minns.

Robinson, who is gay, has caused divisions since he was consecrated as bishop of New Hampshire in 2003.

The deeply conservative Minns was installed last year as the head of a new Nigerian-based church branch in the United States designed as a refuge for orthodox believers. The Anglican communion does not recognise his position.

Williams has battled -- largely in vain -- to placate the warring camps and bemoaned what many see as an Anglican obsession with sex.

In an interview last month with Time Magazine, Williams said of his church: "It feels very vulnerable and fragile, perhaps more so than it's been for a very long time."

But he still insisted that, despite facing one of the gravest threats in the 450-year-old history of the Anglican Church, "I don't think schism is inevitable."