The Archbishop of York has defended the right of Anglican clergy and laity to hold "varying" views on the contentious issue of homosexuality. He called for disputes to be resolved in a "Christianly" matter.

Dr John Sentamu was speaking as evangelical protests grew about links between York Minster and last weekend's gay pride march. Conservative evangelicals are also angry over remarks made by a bishop during an employment tribunal of a gay clergyman denied promotion after he married his partner.

Some are calling on Bishop of Buckingham Alan Wilson to resign after he defended the gay marriage of Rev Jeremy Pemberton. They are also threatening to switch allegiance from the Church of England to the new conservative Gafcon fellowship.

The escalating war of words is a sign that the "conversations" currently taking place over human sexuality in the Church of England come amid a time of intensifying crisis.

In a joint statement, Reform and the Oxford Diocesan Evangelical Fellowship called for the Church of England to "uphold the gospel of Jesus Christ".

Criticising Canon Michael Smith of York Minster for blessing the York Gay Pride march last weekend and Bishop Wilson for describing traditional Christian doctrine on homosexuality as "lousy", Reform and the Oxford evangelicals said the majority of the world's Anglicans already look to the primates of of the Global Anglican Future Conference for leadership.

"The only question is whether after weeks like this one, those in the Church of England who wish to proclaim this Gospel will be forced to follow the same path," they said in what is being interpreted in senior Church circles as a clear warning of possible schism.

"Christianity is based on revealed doctrine, enabling individuals to live rightly before a Holy God as followers of Jesus Christ. He tells us how to live in all areas of life, including in areas of sexual behaviour.

"No denomination is at liberty to invent its own doctrine or to sacrifice revealed doctrine on the altars of contemporary fashion. We cannot be authentically Christian whilst simultaneously rejecting the teaching of the one we claim to follow."

Rev Simon Austen, Rector of St Leonard's Church in the Exeter Diocese said: "York Minster's leading the way in the Gay Pride march is symbolic of what the Church of England's leadership is doing generally on this issue – leading people away from the clear teaching of the Bible and the Gospel. It exposes the sham of the consultation process for what it is – a means by which the church can validate homosexual activity.

"One would hope that the Archbishop of York would do his duty and speak clearly, upholding the Bible's position."

Rev Melvin Tinker, of St John's Church, Newland in the York Diocese said: "I am deeply disappointed that Alan Wilson persists in undermining the teaching of the Church by his overt support of those who have gone against the clear rules governing clergy discipline.

"Describing the Church's teaching and doctrine as lousy is quite breathtakingly arrogant and not language that one would expect from a senior leader in the Church. Were I in secular employment and so at odds with the leadership and core values of the company that employed me, I would resign forthwith as a matter of conscience."

Rev Will Pearson-Gee, Rector of Buckingham in the Oxford Diocese, said: "The Bishop of Buckingham courts publicity for his revisionist agenda and gets it. He has sadly become a figure of disunity in the Oxford Diocese and a cause of grief to many faithful Anglican Christians. The version of marriage he espouses is incompatible with Biblical Christianity."

The Dean of York, Very Rev Vivienne Faull, defended York Minster's support for a section of the community that frequently experiences discrimination and hostility.

"York Minster's invitation to everyone to discover God's love through our welcome, worship, learning and work is extended to the entire community both inside and outside of the Minster. The Church of England is actively encouraging conversations around human sexuality and it is better to have those conversations with friends," she said.

Canon Smith said: "Here at York Minster we are always open to having conversations with anyone who wants to come and talk with us and we are always ready to pray with and to pray for people at important times in their lives. Please do not hesitate to come and talk to us."

In a letter to friends and colleagues in response to the calls for his resignation, seen by Christian Today, Bishop Wilson says he has had hundreds of messages of support of his views on sexuality.

He admits however that not everyone feels the same way about gay marriage. "The great social upheaval this represents, along with the articulation of my own personal viewpoint, is causing them profound distress and anger."

He acknowledges that many colleagues find real difficulty in using the word "marriage" for gay relationships.

"One of the key messages I have been communicating in the media is that local Churches usually welcome all people as Christ did, regardless of gender or sexual orientation. Any stereotype that denies this needs to be challenged."

He also says a growing number of Christians, including many Evangelicals, now fully affirm present realities about same-sex marriage.

"At the same time, a sizeable minority of our own LGBT clergy and lay people feel increasingly unsafe, and that the Church has rejected them. Many of these contact me, sometimes in great distress and pain, and have come to see me as a safe bishop with whom to talk through their stories. It is a great joy to minister reconciliation to people who had lost all hope that they could be part of the Church at all.

"Meanwhile most of the people we serve, especially young people, are baffled as to why this is an issue for us."

He also defends his appearance in Nottingham at Jeremy Pemberton's employment tribunal.

"I was called as an expert witness on the way faith, doctrine and law relate to one another in Church, a subject on which I once spent eight years writing a doctoral thesis. " The case relates also to his recent book and in addition he is an expert on clergy tenure. He also says he is "baffled" by any suggestion that he is somehow living outside canon law. "I have been happily married for over 30 years and am entirely compliant."

He explains he was merely criticising the shortcomings of Canon B30's definition of marriage, not its substance. "I don't, of course, deny marriage is between a man and a woman. I merely wish to see access to it expanded."

He said his argument in the tribunal was that the canon should be applied equally and consistently to gay and straight people.