The Church in the UK is seeing growth, the Archbishop of Canterbury has insisted, despite a major report this week concluding that British churchgoers are in significant decline.

In a lengthy interview with Michael Gove for the Spectator, Archbishop Justin Welby said: "We are seeing many churches growing and particularly I would say that in the last seven or eight years one of the most exciting things has been that, in the aftermath of the Great Recession, we have seen the churches more active in social structures again, in the social events of this country, than at any time since 1945."

"The tide is turning in this country," he said.

A new report by the Commission on Religion and Belief in Public Life claims that there has been a "general decline" in Christian affiliation in Britain, with only two in five people now identifying with the faith.

It calls for national forums such as the House of Lords to reflect "the pluralist character of modern society". Currently, 26 Anglican bishops sit in the House as Lords Spiritual.

Asked whether "in the contemporary clash of ideas Christianity was at a disadvantage" by Gove, however, Welby responded: "No, because in the clash of ideas, Christians believe in the sovereignty of God. We are confident in the Victory of God which is seen – surpassing evil – in the events of the Cross, of the Resurrection and the Ascension."

The Archbishop also insisted that Christians struggle to fall "within the political spectrum", and said he is not "going to fit" firmly on the right or left.

The Church's focus on the importance of family and its role in the provision of social welfare means that it can find itself caught between the two, he added.

Welby was also quizzed on how he would respond if one of his children came out as gay. The issue of homosexuality has been at the forefront of Church debate in recent years, with a significant divide between those who hold to traditional teaching on same-sex relationships and those calling for the Church to be more accepting of gay people.

The Archbishop has so far aligned himself with traditionalists, though he has acknowledged that historically, the Church has caused "great harm" in the way it has approached homosexuality.

He told the Spectator, however, that he would attend the civil ceremony of one of his children, were they to marry someone of the same-sex.

"Would I pray for them together? You bet I would, absolutely. Would I pray with them together? If they wanted me to. If they had a civil service of marriage, would I attend? Of course I would," he said.

"I would say, 'I will always love you, full stop. End of sentence, end of paragraph.' Whatever they say, I will say I always love them."