Downing Street announces on Twitter that the Bishop of Durham, the Rt Rev Justin Welby, will be the next Archbishop of Canterbury.

Rt Rev Justin Welby (pic: Getty)

He said being nominated for the post was "astonishing and exciting".

The Rt Rev Justin Welby, an Eton-educated former oil industry executive, will become the 105th Archbishop and spiritual leader of the 77 million-strong Anglican Communion.

He told a news conference at Lambeth Palace: "This is the best-kept secret since the last Cabinet reshuffle.

"To be nominated to this post is both astonishing and exciting."

Bishop Welby was the fourth most senior cleric in the Church of England before the announcement that he would succeed Rowan Williams.

Please wait while this video loads. If it doesn't load after a few seconds you may need to have Adobe Flash installed.

Announced on Twitter

No 10 made the unusual move of announcing the appointment on social networking site Twitter, stating: "Downing Street is pleased to announce the appointment of Justin Welby as the 105th Archbishop of Canterbury."

Please wait while this video loads. If it doesn't load after a few seconds you may need to have Adobe Flash installed.

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."

Bishop Welby 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 only became a bishop less than a year ago - taking up the post of Bishop of Durham in November 2011. He has also worked as Rowan Williams' special envoy to Africa, attempting to build unity between Christian and Muslim communities in Nigeria.

Several other senior figures in the Church of England were reported as possible contenders to succeed Dr Williams, who leaves after a decade, at the end of this year, to become master of Magdalene College, Cambridge.

They included the Archbishop of York Dr John Sentamu who was named as an early favourite, the Bishop of Norwich the Rt Rev Graham James, and the Bishop of London, the Rt Rev Richard Chartres.