By Alex Kirby BBC News Online correspondent

In choosing the Most Reverend Rowan Williams as the 104th Archbishop of Canterbury, the Church of England may be in for a lively ride.

Dr Williams, who published his first book at the age of 29, was only seven years older when he was appointed professor of divinity at Oxford - the university's youngest professor.

He is the first Welshman - indeed he is a fluent Welsh speaker - to be selected for the Church of England's top job for at least 1,000 years.

Dr Williams is an outstanding theologian, a discipline the Church has increasingly neglected.

Rowan Williams' views

Liberal socially but conservative theologically Backs separation of church and state Accepting of homosexuality Backs ordination of women priests Has criticised any invasion of Iraq Has criticised the war on terror Says divorcees can remarry in church

One observer says Dr Williams' address to the 1998 Lambeth Conference, the meeting staged each decade of all the worldwide Anglican church's bishops, "was seen as the most erudite, though the least understood".

The archbishop is regarded as a liberal, even a radical.

He is sympathetic to the proposal that the Church of England should lose its established status, and become a church on an equal footing with the Catholics, the free churches and all the other Christian denominations.

This is not a view likely to endear him to traditionalists.

Dr Williams also refuses to stigmatise lesbian and gay clergy in the way some of his fellow Anglican bishops have done.

Raising hackles

He has acknowledged knowingly ordaining a practising gay priest, something which raises Anglican hackles as few other issues do.

The archbishop has also criticised Western policy since 11 September, describing the military action in Afghanistan as "morally tainted", and the bombing campaign as morally equivalent to the terrorism it sought to defeat.

Dr Williams has some heavyweight support, notably the endorsement of the former archbishop of Cape Town, Desmond Tutu.

Desmond Tutu: Believed Williams should be chosen

Reverend Tutu said his Welsh colleague "towered head and shoulders" above all the other candidates, and had an incredible capacity to communicate, as well as a deep spirituality.

Rowan Williams is seen as a man of breadth and vision, capable of lifting the Church out of its timid introspection and enabling it again to play a useful part in national life.

Whether he can do so depends above all on two things - the Church's ability to forget its hang-ups over sex, and the establishment's willingness to trust somebody prepared to challenge it.