Dr Williams was preaching at evensong in Armagh, half way through a critical meeting of the primates of the Anglican Communion to discuss the Windsor Report, set up by Dr Williams in an effort to resolve the crisis over homosexuality that has brought the Church to the brink of schism.

He told the primates that Christ called them to be instruments of His peace. He said that the Church was, above all, a place of prayer and thanks-giving. “If the Church fails to be such a place, it is no real Church.” He continued: “We are required first of all to know that it is Christ who has made peace. In other words, we are not to be anxious, a doomed piece of advice it may be for any Church — not least the Anglican Communion at the moment — and yet that is what Christ says to us.

“How readily we turn to anxious striving, as if Christ had not died and been raised. How awkwardly we sit with one another to pray together, to worship together.” But the Church should not close its doors to those “lost in unhappiness, in error and in sin”.

Thirty-five of the 38 primates who head the provinces of the 77 million-strong worldwide Anglican Communion are meeting at the Dromantine Centre, a Roman Catholic monastic retreat near Armagh.

Hymns at the hour-long service at the city’s 13th-century St Patrick’s cathedral included one with repeated invocations of God the Trinity, the traditional symbol of unity, against “the natural lusts that war within” and “against false words of heresy”.

The primates also sang Psalm 133: “Behold how good and joyful a thing it is, brethren, to dwell together in unity!” The service, attended by Paul Murphy, the Northern Ireland Secretary of State, was the culmination of two days of debate in which conservative archbishops won the first round in the battle for the soul of the Anglican Church yesterday when they “tore up” the agenda of the week-long meeting.

Led by the primate of Nigeria, Dr Peter Akinola and primate of Central Africa, Dr Bernard Malango, the anti-gay evangelicals used their numerical strength to force the meeting to put subjects such as Aids and world poverty on the back burner and to spend all week debating the threatened schism over homosexuality.

Insiders said Dr Williams had seemed sympathetic to the demands of the conservatives.

But in his sermon he indicated that it might not be the best thing to strive to reach a firm resolution of the issues in the immediate future. “Our own efforts at peacemaking and witnessing to peace in world and Church alike must not be characterised by anxious striving, by desperate activism, by the passion to get it all sorted out right now,” he said.

The discussions will continue until the end of the week.