The Archbishop of Canterbury Justin Welby has said that his stance against same-sex marriage could be seen as “wicked”.

The Most Rev Justin Welby told an audience of traditional born-again Christians on Wednesday that they must “repent” over the way gay and lesbian people have been treated in the past and said most young people viewed Christians as no better than racists on the issue.

Speaking at the official opening of the Evangelical Alliance’s new premises in King’s Cross, London, he said that today’s society had evolving views about sexuality and many younger people thought that opposition to equal marriage was “plain wrong”.

Mentioning how he voted earlier this summer against the Marriage (Same Sex Couples) Act, Archbishop Welby said: “What I voted against was what seemed to me to be the rewriting [of] the nature of marriage in a way that I have to say within the Christian tradition and within scripture and within our understanding is not the right way to deal with the very important issues that were attempted to be dealt with in that bill.

“The bill was clearly, quite rightly, trying to deal with issues of homophobia in our society.

“As I said at the time in the House of Lords, the Church has not been good at dealing with homophobia – it has at times, as God’s people, either implicitly or explicitly supported it and we have to be really, really repentant about that because it is utterly and totally wrong.

“But that doesn’t mean that redefining marriage is the right way forward.

“That discussion is continuing and the Church is deeply and profoundly divided over the way forward on it.

“I am absolutely committed not to exclude people who have a different view from me, I am also absolutely committed to listening very carefully to them.

“If the same thing happened again I would vote the same way as I did then but I am continuing to think and listen very carefully as to how in our society today we respond to what is the most rapid cultural change in this area than there has been for a very long time.

“We have seen changes in the idea about sexuality, sexual behaviour.

“We have to face the fact that the vast majority of people under 35 not only think that what we’re saying is incomprehensible but also think that we’re plain wrong and wicked and equate it to racism and other forms of gross and atrocious injustice.

“We have to be real about that.

“I haven’t got the answer one way or the other until my mind is clear on this.

“I’m not going to get into the trenches.”

Benjamin Cohen, founder of campaign group Out4Marriage and publisher of PinkNews, said: “It is welcome that the Archbishop of Canterbury has recognised that the majority of people under the age of 35 do not consider same-sex relationships as anything other than normal.

“They do see that attacking gay people for the gender of the person that they love is as evil and incomprehensible as attacking someone for being born black or disabled. People don’t chose to be gay just like they don’t chose their race.

“I would not argue that the Archbishop’s stance was ‘wicked’. All the way through the debate on same-sex marriage, those of us in favour of the change always maintained that churches, synagogues and mosques should be free not to opt-in to same-sex marriage. This is their right. Just as it is the right of the younger generations to question the relevance of these institutions if they reject a change in the law that most young people think is nothing more than equality.”

Archbishop Welby admitted that the Church’s opposition to equal marriage was “utterly overwhelmed” by vocal supporters in July.

Earlier this month his predecessor, Dr Rowan Williams admitted he regularly questioned whether he had let gay and lesbian people down during his time in post. 

“I know that is what a great many of my gay and lesbian friends would say that I did,” Dr Williams said to an audience at the Edinburgh International Book Festival.