[Dr Carey] has worked tirelessly at home and abroad

Prime Minister's official spokesman

"[Mr Blair] has great admiration and respect for the work that he has done over the last decade in guiding the Church through a period of change," he said.

"He has worked tirelessly at home and abroad in his role as head of the Anglican communion."

Dr Carey could have stayed in his post until he turns 70 in 2005 but said the time would be right to end his tenure after the Queen's Golden Jubilee.

In a statement Dr Carey said: "By the end of October I shall have served 11 and half years in a demanding yet wonderfully absorbing and rewarding post.

Exciting opportunities

"I feel certain this will be the right and proper time to stand down.

"I look forward to exciting opportunities and challenges in the coming months, and then to fresh ones in the years that follow."

Lambeth Palace said Dr Carey will carry on with all his duties as normal up to his last day in office on 31 October.

Committed Christian Tony Blair praised the archbishop

Dr Carey has had an eventful and often difficult reign since he was appointed the 103rd Archbishop of Canterbury in 1991.

His main achievement was to oversee the first ordination of women priests in 1994 and manage the deep divisions it created within the Church of England.

Tributes came from bishops and other religious leaders to Dr Carey, who became the 103rd Archbishop of Canterbury in 1991.

The leader of Roman Catholics in England and Wales, Cardinal Cormac Murphy-O'Connor, praised Dr Carey's achievements and said he would be greatly missed.

Difficult times

He said: "As leader of the Anglican Communion he emerged as someone of immense integrity, zeal and courage."

The Chief Rabbi, Professor Jonathan Sacks, described Dr Carey as a "humane, warm and caring face" of Christianity who was a "blessed presence in British life".

"He is a man who has kept his integrity and spirituality intact during difficult times and has thus been a compelling example of what it is to be religious in a secular age."

Some of the bishops tipped to succeed Dr Carey were at the forefront of the tributes.

Significant work

Dr Rowan Williams, the Archbishop of Wales, is a respected theologian and writer

He said: "Apart from the highly significant work he has done for the Church of England, he has contributed more than most will realise to churches in the developing countries by his practical support and brave advocacy, especially for Christians in minority situations."

The Bishop of Rochester, Michael Nazir-Ali, also paid tribute to Dr Carey's skill in bringing together different religions.

"In his worldwide role, his appreciation of the importance of Islam must be, in the light of recent events, seen as prophetic.

Renewed struggle

"The establishment of dialogue with different traditions in Islam is nothing short of pioneering."

Dr Carey, the son of an East End porter, has often been seen as a man of the people - he was the first Archbishop of Canterbury in modern times not to have attended Oxford or Cambridge universities.

And his departure will see renewed struggle between the conservative and liberal wings of the church, over his successor.

Other politicians have been offering their tributes to the archbishop, with Conservative leader Iain Duncan Smith speaking of his "deep sense of commitment".

And Tory MP Ann Widdecombe, who herself left the Church of England after it started ordaining women priests, acknowledged Dr Carey's achievements during "monumentally difficult times" for the Church.