Archbishop Justin Welby speaks out on gay relationships as he agrees to meet campaigner Peter Tatchell

The Most Rev Justin Welby has warned that "children and families will pay the price" if plans to change the system go ahead in their current form, The Sunday Telegraph said. (EPA)

The head of the Church of England has said some gay couples have loving and monogamous relationships of "stunning quality" - and he believes a woman will one day be made an archbishop.

The Most Rev Justin Welby said he backed traditional Church teaching on homosexuality but told BBC News: "You see gay relationships that are just stunning in the quality of the relationship."

The Archbishop, who is being enthroned at Canterbury Cathedral today, added that he had "particular friends where I recognise that and am deeply challenged by it".

In a separate interview with Channel 5 News, the Most Rev Welby said he believed there would be a female archbishop one day in spite of the defeat of women bishops legislation last November.

Pressed on the timing, he said: "Oh, I have no idea... when the right person turns up. But, yes, I think there certainly will."

His remarks came as he was due to begin his public ministry as head of the Church of England, spiritual leader of the 77-million strong Anglican Communion and 105th Archbishop of Canterbury.

The Prince of Wales and the Duchess of Cornwall as well as Prime Minister David Cameron will be among around 2,000 people attending the ceremony.

In a separate development, it was revealed that Archbishop Welby sent a letter last night to veteran human rights campaigner Peter Tatchell, offering to meet him face to face.

The invitation was in response to an open letter in which Mr Tatchell accused the Archbishop of being "homophobic" by opposing gay marriage and said that some local Anglicans had colluded in persecution of gay people in Africa.

In his response, Archbishop Welby thanked Mr Tatchell for his "very thoughtful" letter and said the points he had made were "powerful."

Those in the congregation at the Canterbury service today include representatives of major world religions including Muslims, Jews and Sikhs and senior figures from the Roman Catholic and orthodox churches.

The event marks the formal reception of Archbishop Welby, 57, at Canterbury, the mother church of the Church of England and of the Anglican Communion.

It is the last stage in his appointment following his confirmation of election at St Paul's Cathedral last month.

The post of Archbishop of Canterbury combines several roles. Archbishop Welby is diocesan bishop of Canterbury, head of the southern province of the Church of England and senior bishop of all England.

He is also leader of the Anglican communion worldwide.

PA