Meanwhile the Rt Rev Colin Fetcher, the Bishop of Dorchester, said the church's teaching on sexuality should not be treated as a core doctrine like the trinity, from which anyone who disagrees is a "heretic".

The pair are among a line-up of prominent clerics, including the Dean of St Paul's, London, the Very Rev David Ison, who have contributed to a new book of essays by leading figures from an evangelical background calling for the Church to move to a stance of "affirming" people in same-sex relationships.

Rt Rev Colin Fetcher said the church's teaching on sexuality should not be treated as a core doctrine

Neither of the two bishop calls for traditional teaching on family issues to be abandoned.

But they say that those who do not accept traditional teaching should not be excluded.

Their intervention will anger traditionalists in the Church of England and could further inflame tensions with Anglican leaders in Africa and elsewhere.

Bishops Bayes said he had been "profoundly changed" by encounters with lesbian and gay Christians in recent years - including within his own family.

"I have come to believe that we need to change the church," he writes.

He argues for a wholesale reappraisal of traditional interpretations of the Bible relating to sex and marriage.

"As the tradition of celibacy indicates, the command to multiply is not the primary calling for the Christian Church -- indeed human success in breeding and survival threatens the very viability of our planet," he writes.

"Some reconsideration of how we should now understand the Genesis perspective on marriage is necessary, as well as exploration on how far that should affect the underlying principles.

"And that exploration continues. My views on the few explicit biblical texts on 'homosexual practice' (which is an anomalous term for biblical times) are open not closed -- particularly as we continue to engage with the dialogue between texts and contexts."

In a foreword to the book, Bishop Fletcher adds: "I confess that I get worried when I am told -- as I was very recently -- that this is a 'Gospel Issue'.

"I reflected on this afterwards and I concluded that what the speaker meant was that this would be some form of heresy and that they would leave the Church of England if we ever accepted same-sex blessings or marriages.

"Whilst I fully agreed with them that questions to do with humanity and sexuality are not merely matters of marginal interest or indifference, I do want to challenge the assertion that places them on an equal footing with the great credal truths of the Trinity or the humanity and divinity of Christ."

The book's Editor, Jayne Ozanne, a member of the General Synod, said: "There is a growing number of voices across the Church, including the 'Evangelical wing', that believe that it is possible to hold an affirming biblical view of same-sex relationships, and who want to affirm LGBTI Christians for being who they are in Christ.

"For too long people have felt silenced for saying what they truly believe for fear of being called unsound by their colleagues -- the time for silence is now over."

END