The Archbishop of Canterbury's efforts to keep the Church of England together might be torpedoed by evangelicals who refuse to compromise on what they regard as fundamental issues of faith – but that might not be a bad thing, according to a leading academic.

In his address to the General Synod this week, Justin Welby issued a call for unity amid the tensions threatening the Anglican Communion and the Church of England itself over issues such as same-sex relationships. He said: "In many parts of the Communion, including here, there is a belief that opponents are either faithless to the tradition, or by contrast that they are cruel, judgemental, inhuman. I have to say that we are in a state so delicate that without prayer and repentance, it is hard to see how we can avoid some serious fractures."

He added: "In this Church of England we must learn to hold in the right order our calling to be one and our calling to advance our own particular position and seek our own particular views to prevail in the Church generally, whether in England or around the world. We must speak the truth in love."

However, a recent YouGov survey of 1,500 Church of England clergy commissioned by the Westminster Faith Debates found that "a relatively small group of the most evangelical male clergy" could stand in the way of the Archbishop's goal.

Roughly a third of clergy identify as evangelical. Of these, 88 per cent say that same-sex marriage is wrong, compared with just over a third of the rest of the clergy. Similarly, 31 per cent of evangelical clergy would ban abortion altogether, a figure which falls to 16 per cent among Anglican clergy overall.

While these views themselves are no bar to Church unity, the survey also shows that evangelicals are far less willing to compromise. It found that: "While the majority of clergy support the aim of 'maintaining unity by being more tolerant of diverse views,' two thirds of the evangelical clergy disagree, contending either that the Church should seek greater uniformity of views or else that it should not be afraid of separating amicably along doctrinal and ethical lines."

The survey also found that it was evangelical men rather than evangelical women whoare opposed to the Archbishop's goal of 'disagreeing well.' Most evangelical women clergy (61 per cent) agree with the majority of clergy who support greater toleration. But 68 per cent of evangelical male clergy disagree.

Lancaster University's Prof Linda Woodhead said: "These findings are both good and bad news for the Archbishop – good in that his battle is won with most of the clergy and almost certainly an overwhelming majority of lay Anglicans. Bad, in that there is a significant group of male clergy who do not share his vision for the CofE and the Anglican Communion."

However, she told Christian Today that trying to hold the different wings of the Church of England together was not necessarily a useful strategy in terms of meeting the challenges of decline and societal change. "My view is that it would be much better to enable people to function in smaller groups and enable people to do their own thing rather than to try to hold on to a lowest common denominator," she said.

"If I were in church leadership and saw these statistics I would think very hard about whether I really wanted to cast things loose rather than trying to keep people together. It would lessen tensions and release a lot of energy."

She suggested that "a looser, federal structure, a framework in which people could buy in central services for different branches, each of which could have its own internal organisation and set its own strategy" might be a more appropriate model in the modern context. She said that as the Church of England was a state church, not a gathered church, it would inevitably have to accommodate more variety as society itself became more diverse.

Rev Simon Austen, vicar of St Leonard's, Exeter, and a member of the council of the conservative evangelical Reform group, told Christian Today that while unity was important and was "the platform for a loving, enabling discussion", it was "defined by how we relate to the Lord Jesus Christ and how we conform to his likeness". "We are not able to believe whatever we want. We have a framework that defines our unity," he said, noting that the vast majority of Anglicans worldwide took a traditional position on same-sex relationships and sexual ethics generally.

He said: "The real issue is over that which jeopardises our salvation. If the Church of England were to say, 'This is not really sinful and you don't need to repent of it,' it would be redefining salvation. It would be very difficult if one part were to say that you need to repent of this behaviour and another part were to say that you don't."

He added: "I think what we need to help the world realise is the wonderful grace that calls us to a a different life, and have confidence in that. We are not just in the business of mirroring what the world thinks. We bring something wonderfully different."

Austen said it was "hard to answer" the question whether the Church of England could remain together: "The question is, to what extent those wishing to change would depart from the orthodox line."

Academic and blogger Rev Dr Ian Paul, a member of the centre-evangelical Fulcrum group's leadership team, told Christian Today that while Justin Welby valued unity, it would be wrong to suggest that he believed it was more important than any other issue.

He added: "On the question of same-sex marriage, the heart of the question is precisely whether this can be considered one of the adiaphora, a subject on which we can agree to disagree, or whether a change of the Church's position would go to the heart of Anglican identity by changing its relationship with Scripture as the key source of its theological views.

"So the views of male evangelical clergy are not an 'obstacle' to Justin's goal. Rather, they highlight what this debate is about: can we agree to disagree, or is this issue more central than that?"

He also suggested that because evangelical churches tend to be larger than non-evangelical, resistance to same-sex marriage in the Church of England as a whole was likely to be stronger than the survey of clergy indicated.

A Westminster Faith Debate entitled Diversity – what kind of unity is appropriate nationally and internationally, how can diversity become a strength? will be held tonight, November 20, at the University Church, Oxford, from 5:30-7pm.