John Sentamu, 62, the Archbishop of York, is widely viewed as front-runner to replace Rowan Williams as the Archbishop of Canterbury when he leaves at the end of this year.
Dr Sentamu, the sixth of 13 brothers and sisters, and a former barrister and judge, came to the UK in 1974 having fled Uganda where he was a critic of the dictator Idi Amin.
Dubbed by some as "cleric of the people", he is known for his high-profile interventions.
In 2007 he cut up his dog collar on live television in a dramatic protest against Robert Mugabe's rule, vowing never to wear the symbol of his office again until the Zimbabwe president had been removed from power.
Dr Sentamu also once pitched a tent and camped in York Minster for a week, foregoing food, in solidarity with those who had suffered in the Middle East conflict.
The Archbishop has gained a reputation for supporting the armed forces - sky-diving to raise money for families of servicemen wounded or killed in Afghanistan - and for speaking out against bankers and traders responsible for the financial crisis.
He has called for the English to mark St George's Day properly on April 23, warning that the failure of England to rediscover its culture would lead only to greater political extremism.
Dr Sentamu's enthronement in 2005 featured a ceremony with African singing and dancing and contemporary music, with Dr Sentamu playing African drums during the service.
He was named Yorkshire Man of the Year in 2007.
"It is with great sadness that I received the news that the Archbishop of Canterbury will be stepping down at the end of this year. Our partnership in the gospel over the past six years has been the most creative period of my ministry. It has been life-giving to have led missions together, gone on retreats and prayed together. In his company I have drunk deeply from the wells of God's mercy and love and it has all been joyful. He is a real brother to me in Christ. The last decade has been a challenging time for the Church of England and the Anglican Communion. Thankfully, Archbishop Rowan is a remarkable and gifted leader who has strengthened the bonds of affection. Despite his courageous, tireless and holy endeavour, he has been much maligned by people who should have known better. For my part he has been God's apostle for our time. His stepping down to pursue something he dearly loves - teaching and writing - is received with gratitude, as this will continue to be a blessing to the Church. I am delighted that he is not going far away and will continue to offer service to the Church of England and the wider Church in its witness to our society. May God's blessing continue to be showered upon him. More will be said nearer his time of departure. For now, Archbishop Rowan, Jane and the family will remain in our prayers."