Steve Chalke has elaborated on comments he made in support of homosexuality last month.
The Baptist minister was criticised for his views in a Christianity magazine article endorsing faithful, committed and permanent same-sex relationships.
Addressing his critics in a video, Chalke said he had felt the need to make a public statement after wrestling with the issue.
He said his intention had been to promote an honest and respectful discussion among Christians about the question of homosexuality.
After receiving "tens of thousands" of responses both for and against his position, Chalke said he was "really pleased" with the debate that had opened up following the publication of his article.
"It was a taboo. Now we can talk about it openly and that's got to be a healthy thing," he said.
Addressing the charge that his position overturns Scripture and 2,000 years of church history, Chalke said he had not abandoned the Bible and that the church had changed its position on several major issues, like slavery, women, and divorce.
"In what I've said I've not sought to abandon the Bible at all. Indeed, I've sought to wrestle with it, to grapple with it, to take it very seriously. I believe the Bible, I believe the whole Bible actually. The Old Testament, every word of it. The New Testament, every word of that."
He continued: "Some of my critics have said the Bible's absolutely clear about homosexuality, but one thing that's absolutely clear even from reading their responses is that the Bible is not absolutely clear at all."
In his original article, Chalke criticised the way in which gay people had been treated in churches. He took this concern up again in the video, saying the church's attitude to gay people would never change unless its theology changed.
"Now we've begun talking, we've got to keep talking ... because if we all just restate positions and then sweep it all back under the carpet, people's lives will continue to be ruined. I think we've got to do our practice better, I think we've got to do our theology better as well," he said.
He continued by saying that the 'love the sinner, hate the sin' approach "isn't at all applicable" in the case of gay people because he did not believe homosexuality to be a sin.
"I don't think that being homosexual is a sin so to call someone who is homosexual a sinner for that reason is a category error and I don't think it's an error the New Testament makes," he said.
Instead, Chalke said it was the responsibility of the church to call people to lifelong, committed relationships, regardless of whether they were heterosexual or homosexual.
"[A] lifelong, loving permanent relationship is not against what the Bible teaches at all and I believe, driven by the ethic of Jesus, then actually the church should get behind those relationships and endorse them, instead of leaving gay people in a world where they have to pretend they are something they are not and often live lives of deception," he said.
Chalke said he was not arguing for or against gay marriage, but instead calling the church to be more inclusive and embrace an "open evangelicalism" in which the Bible is constantly explored.
"Open evangelicalism: that's the challenge for us all," he said.