Media playback is unsupported on your device Media caption The Rt Rev Justin Welby: ''To be nominated to this post is both astonishing and exciting.''

The next Archbishop of Canterbury has set out his support for the ordination of women bishops, as his appointment was officially confirmed.

The Bishop of Durham, the Rt Rev Justin Welby, 56, said his appointment was "astonishing and exciting".

On the issue of same-sex marriage he said he had to examine his own thinking "carefully and prayerfully".

He will take on the Church of England's most senior post at a ceremony at Canterbury Cathedral on 21 March 2013.

Bishop Welby will become the 105th Archbishop of Canterbury, replacing Rowan Williams who retires in December after 10 years in the role.

At a press conference at Lambeth Palace on Friday, Bishop Welby said it was a time for "optimism and for faith" in the Church.

His appointment comes as the Church of England faces controversial issues, including a vote in 10 days' time on ordaining women bishops.

Analysis Justin Welby's appearance was characterised by one very important quality - his steeliness. You could hear it in his voice as he spoke about the challenges facing the Church and what he hoped to bring to the table. And it was also apparent in the straightforward way he spoke about engaging with the gay community, and his clear backing for women bishops. He very neatly dodged a question from me about conflict resolution in the Church, but also showed he had a sense of humour, telling journalists the difference between him and Rowan Williams was that he had a better barber - and razor. Read more from John McManus Listen: Radio 4's profile of Justin Welby

"I will be voting in favour and join my voice to many others in urging the synod to go forward with this change," he said.

He also said the Church faced deep differences on the issue of same-sex marriage.

"It is absolutely right for the state to define the rights and status of people cohabiting in different forms of relationships, including civil partnerships," he said.

"We must have no truck with any form of homophobia in any part of the Church. The Church of England is part of the worldwide Church, and has responsibilities that come from those links. What the Church does here deeply affects the already greatly suffering churches in places... like Nigeria."

He added: "I am always averse to the language of exclusion, when what we are called to is to love in the same way as Jesus Christ loves us. Above all in the Church we need to create safe spaces for these issues to be discussed in honesty and in love."

He also said he was optimistic about the future of the Church.

"The Church will certainly get things wrong, I certainly will get things wrong. We will also get much right and do so already."

'Overwhelming choice'

The Most Reverend Rowan Williams said he was delighted by the appointment.

"I have had the privilege of working closely with him on various occasions and have always been enriched and encouraged by the experience," he said.

"He has an extraordinary range of skills and is a person of grace, patience, wisdom and humour. He will bring to this office both a rich pastoral experience and a keen sense of international priorities, for Church and world."

Prime Minister David Cameron, who confirmed Bishop Welby's appointment via Twitter, said he "wished him success in his new role".

Media playback is unsupported on your device Media caption The BBC's Will Ross looks at the challenges facing the new Archbishop

Speaking during a visit to Carlisle, Mr Cameron added that the new archbishop had been the "overwhelming choice" of the panel set up by the prime minister to find a replacement for Dr Williams.

"I think having someone who had a life outside the Church in business, who understands difficult, complicated issues, will bring a great breath of fresh air to the Church of England," he said.

Bishop Welby, who has had six children with wife Caroline, was educated at Eton and Cambridge University, and then spent 11 years in the oil industry before studying theology at Durham. He was ordained in 1992.

He became Rector of Southam in 1995 and was later appointed canon residentiary of Coventry Cathedral. He left the area in 2007 when he was appointed Dean of Liverpool.

He took up the post of Bishop of Durham in November 2011 and worked as Dr Williams' special envoy to Africa, attempting to build unity between Christian and Muslim communities in Nigeria.

Bishop Welby is regarded by observers as being on the evangelical wing of the Church, closely adhering to traditional interpretations of the Bible with a strong emphasis on making the Church outward-looking.

Even within the evangelical community, however, there are significant differences of outlook on questions of doctrine.