The openly gay bishop whose consecration led to the crisis over sexuality in the Anglican Communion has accused his evangelical opponents of “idolatry”.

The Bishop of New Hampshire, the Right Rev Gene Robinson, is to defy the Archbishop of Canterbury by turning up uninvited at Canterbury for the Lambeth conference this week.

The Times has learnt that the crisis is likely to worsen, whatever is decided at the conference, because the Episcopal Church of the US plans to overturn its pledge not to consecrate any more openly gay or lesbian bishops.

The US church, which will dominate the conference with 125 bishops attending, is expected then to elect rapidly and consecrate a further five or six such bishops.

Faced with a church in rapidly increasing danger of schism, the Archbishop of Canterbury decided weeks ago to make the ten-yearly Lambeth conference, which begins this week in Canterbury, an event devoid of votes, resolutions and plenaries.

The 700 invited bishops, reduced in number because 200 Africans and Asians are boycotting the conference in protest at gay ordination, are to spend nearly the entire three weeks sequestered in private “indaba” groups at which they will pray, “share” and learn to love each other more. Yesterday it became clear that Dr Rowan Williams's efforts to secure unity, by eschewing controversy, were doomed.

A hectic round of media interviews by Bishop Robinson ensured that the issue of gays and Anglicans remained top of the news agenda, where it is likely to stay for the next three weeks of the conference.

Six US bishops, including the Right Rev John Chane of Washington, are backing a move to bring hundreds more gay and lesbian clergy and lay people uninvited to the conference.

Bishop Robinson, speaking to The Times at St Mary's Church, Putney, before preaching there last night, said he did not believe that the refusal to invite him was homophobic. “I would prefer to call it a lost opportunity,” he said.

He also lamented the Church's obsession with sex. “When young men are knifing each other on the streets of London and a billion or more people are living on less than $1 a day, why is the Anglican Communion tearing itself apart over two men wanting to make a Christian family together?”

Adding that he was totally orthodox on doctrines such as the Trinity, the Resurrection and the Virgin Birth, he said: “We are fighting over something that is much less than all those. We have raised this one issue of sexuality over and above all the essentials. This is at best unhelpful — and at worst idolatry.”

Bishop Robinson will receive backing today from the actor Sir Ian McKellen who will join him at the UK premiere in London of For the Bible Tells Me So, an American documentary about homosexuality and the Bible. Yesterday Sir Ian compared the Church to the Armed Forces and schools in their hostility to homosexuals.

Speaking on the Andrew Marr Show on BBC1, he said: “That particular problem is homophobia and, having [that], they root around in the Bible for the bits that seem to be relevant.”

Bishop Robinson was also backed by the US church's Presiding Bishop, the Most Rev Katharine Jefferts Schori, who preached at Salisbury Cathedral, where the Dean, the Very Rev June Osborne, is among the favourites to become the Church of England's first woman bishop.

Bishop Jefferts Schori called for a “softening of hearts”. She said: “God's grace and favour still falls on people some societies find inappropriate ...

“Many supposedly Christian nations find it difficult to treat immigrants as worthy recipients of full Christian welcome and hospitality. We often see the same attitudes toward gay people. At times we've treated the mentally disabled with equal disdain.”

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