John Sentamu: Pilgrim's progress

John Sentamu is surprisingly slight in the flesh - much less substantial than on television. And despite his ready laugh and broad, gap-toothed smile he has an unassuming manner that sits oddly with his status as one of the most charismatic religious leaders Britain has seen for years. When the letter arrived from Downing Street confirming his latest appointment - as Archbishop of York - he was, he says, "genuinely surprised. I was like John McEnroe: 'You cannot be serious!' If I didn't know Tony Blair's handwriting, I would not have believed it."

Sure enough, the letter was genuine. Next Wednesday, Sentamu will be enthroned at York Minster as the first black archbishop in the predominantly white Church of England. For the first time in decades, there is a sense of expectation about the appointment that goes well beyond the shrinking boundaries of the Anglican Church. Sentamu is expected to make waves.

This is not just because of his record as a colourful, media-friendly churchman - most recently as Bishop of Birmingham - but because of his inspiring life-story. His enthronement is yet another remarkable milestone in a remarkable journey. Born in Uganda into a family of 13, he trained as a lawyer, fled a brutal dictator and arrived in the UK as an asylum-seeker. Since then he has gained a PhD, become a priest and worked in tough inner-city parishes. He has become known as a passionate and effective campaigner against racism, guns and gang culture. And he has been an outspoken critic of government policy on issues ranging from education to the invasion of Iraq.

Since his appointment was announced five months ago, he has spent much of his time responding personally to some 4,000 letters from well-wishers. There have, he said recently, been "a few nasties" in the postbag too - by which he means a handful of racist hate mail, some of it smeared with excrement.

"You ask yourself, 'Why has a person who has never met me done this?' And because it is anonymous, I can't write back or invite them for a cup of tea." Instead, he prays for them. "Jesus said you should pray for people who persecute you. Persecution is a bit strong here, but he meant those who don't like you. You can't be angry with a person you are praying for."

It's not his first encounter with Britain's uglier, racist face. The very first time he took a funeral, the son of the deceased asked: "What has my father done to be buried by a black monkey?" In the 1980s, the National Front tried to burn down his house. When he lived in London, he was stopped by the Metropolitan Police six times in eight years under their stop-and-search policy.

On one occasion, he was pulled over by an officer who asked him what he did. "I said, 'I'm the Bishop of Stepney,' and his whole attitude changed. What annoyed me was the lack of reasonable grounds to suspect me of anything. Middle-aged bishops are rarely a danger to the public."

Generally, though, his faith that Britain is a welcoming country is unshaken. "There are some parts of Europe where you never feel at home," he says. "In the main, Britain is a welcoming community to the stranger."

This welcome is what made a new life possible for Sentamu and his wife Margaret, when they were forced to flee Uganda in the 1970s. Born near Kampala, he was such a frail, blue baby that he was not expected to last his first night. But he eventually thrived, and went to school: he had to walk the 12 miles each way until his English teacher took pity on him and bought him a bicycle. He went on to study law at Makere University.

By his mid-twenties he had become a barrister and a high-court judge. By then Idi Amin was in power, and the young but influential Sentamu put his head above the parapet enough times to attract unfavourable attention. There were the 10 innocent people he sent to jail for their own safety; there was his outspokenness against the deportation of Ugandan Asians; and there was his refusal to overlook the crimes of one of Amin's cousins, whom he sent to prison. He was badly beaten by Amin's thugs, and suffered severe internal bleeding; the injuries still trouble him today.

Finally, in 1974, he was lucky enough to escape to Britain. He became a post-graduate student at Cambridge, where he studied theology and met Rowan Williams (now Archbishop of Canterbury). His decision to enter the priesthood was reinforced in 1977 when, back in Uganda, his friend and mentor Archbishop Janani Luwum was murdered. "You kill my friend, I take his place," Sentamu vowed.

His adopted country has not always seemed a very safe place in which to fulfil this vow. In 2002, for example, he was hospitalised after being pushed down a London escalator in a racist attack. But he remains immensely proud of "this great nation of ours", and you can sense his pride in the sadness with which he speaks about the terrorist attacks on London in July.

He rejects Victor Hugo's view that violence is the voice of the unheard: there is, he believes, no possible justification for such atrocities. "In a community like Britain where you have the opportunity for debate and discussion, the use of violence is totally unacceptable. These terrible acts can never be justified. It's no good to say you are angry, and that drives you to do x, y and z. You know [in Star Wars] Obi-Wan Kenobi says to Luke Skywalker, 'Fear leads to anger, anger leads to hatred, and hatred leads to the dark force.'" He chuckles and rocks forward in his chair, although he is making a serious point. "I think that analysis is right."

Admirers of Sentamu often mention his lively conversation style and his ability to be simultaneously serious and amused. He throws in a reference to Big Brother in one breath and to the Confessions of St Augustine in the next. He has an aphorism or proverb for every occasion. ("In Africa we say, 'Whoever stands out in the crowd does so because he is standing on the shoulders of others,'" he says of his new appointment.)

"He has a precious and wonderful capacity to laugh," says one friend. "He is not frivolous, but sees that nothing is so serious it can't be lightened by laughter. And there are a lot of desperately serious bishops around."

He has raised some eyebrows with his plans for his enthronement at York - instead of a formal sit-down meal after the service, Sentamu has requested a picnic lunch for 3,500, supplied by Marks & Spencer, so that the event can be thrown open to a much wider public than usually attends such events.

Compared with his inauguration in Birmingham, where he became bishop in 2002, this is tame stuff. Then, he arrived at the Cathedral on foot, via the Metro, and circled the Cathedral with a troupe of children and African drummers before entering the building. He declared himself "Bishop for Birmingham" rather than "Bishop of Birmingham", and set about winning the hearts of the entire city, whether or not they were interested in the Church. The delighted local media dubbed him the "rocking bishop".

But there is much more to him than his sure common touch. He is respected in the corridors of power, where he has no fear of rocking boats when he thinks he can make a difference. For example, his background and legal training meant that he was ideally placed to serve as an adviser to the Stephen Lawrence Inquiry from 1997 to 1999, which found clear evidence of "institutional racism" in the Met. (This provoked more racist threats, one of which consisted of a photograph of the murdered teenager with "You are next" written under it in red ink.)

In 2000, when the 10-year-old Damilola Taylor was stabbed and left to die in Peckham, Sentamu was asked to chair a review into the investigation. His report once again found "serious failings" in the way the police had responded and called for fundamental changes to the criminal-justice system which he said favoured defendants over their victims.

Such experiences have left a lasting impression. "I am someone whose theology is grounded in practice," he says. "Sitting on the Stephen Lawrence Inquiry and hearing the terrible evidence can't but shape you, the Damilola Taylor case can't but shape you, engaging with gun crime can't but shape you, coming out of Uganda's difficulties can't but give you a certain perspective."

In February 2003, while thousands marched in London, he led church-wide protests in Birmingham against the invasion of Iraq. "There is no moral basis for a military invasion of Iraq," he said at the time. "The very, very clear message is that the Government should listen. And if they do not listen, I am afraid we are going to be in great difficulties in the future."

Today, he insists, there is no point in saying "I told you so". He adds: "To pull out now would not be responsible. These insurgents can't be allowed to win. My heart is torn apart, not so much because people are being killed but because of the grounds on which we went to war. They still haven't found the weapons of mass destruction: we've had the rug pulled from under our feet."

But there is some room for optimism, he believes. "Passing the constitution is no mean task, believe me," he says. "And people forget that Iraq was already a very violent place. In Uganda it has taken a long, long time to cure. My hope is that the Iraqi people will achieve a self-determining future and that peace will reign and that our solders are able to come back feeling their friends didn't die in vain."

He has exchanged plenty of letters with the Prime Minister on this and other subjects - hence his familiarity with Mr Blair's handwriting - and he expects to continue doing so. But he insists that he will write in praise as well as criticism. He believes the Blair government has a strong track record on education, health, unemployment and the economy.

"The trouble in this country is that there is no balanced view of leadership, and we don't recognise that the Government will get some things right and some things wrong. It would be a good thing if our MPs could think, 'How could we improve education, health, policing?' without shouting at each other from opposite sides of the House. These are not party political but national issues. Why is it always wrong to have consensus? Why pretend they would do it differently, especially when they are all fighting over the centre ground? That's urinal diplomacy and it must stop."

He is convinced that the Church retains an important role in public life. "We may be a bit thin on the ground, but we are still one of the biggest voluntary organisations in Britain, if you take all the faith communities together.

"If we pulled out of all the help-your-neighbour schemes, the country would be in a mess. There are old people's lunches, urban projects, mother-and-toddler groups, the Mothers' Union giving tea to prison visitors - I could go on and on. The Church needs to be there in the pressure areas, where no one else will go. We must practise our presence. That presence is not about people becoming Christians, but about nurturing friendships, creating neighbourliness and a sense of belonging."

The Church is uniquely placed to hear the voice of the poor, he says. "My predecessor Archbishop William Temple went to the East End with William Beveridge to make friends with people. He said that the poverty was visible and smellable and intractable, and something had to be done. Out of that came the welfare state.

"The Church today has got to find the poor, the disaffected and disadvantaged and make friends with them. The trouble is, we don't like listening. My mother used to say, 'John, God gave you one mouth, two eyes and two ears. Use them in proportion.' So I try to listen twice as much as I speak."

People are still drawn to the Church in times of need, he says. "When Diana died, and after the Soham murders, people ran to churches to burn candles. Where else in modern Britain would you have held that service in St Paul's [for the victims of 7 July]? In a football stadium? A mosque? St Paul's Cathedral offered a very clear public service when people were in pain."

None the less, he knows that the Church has sometimes fallen short. "Something about our language of hope has not come through. Instead, there's been something more moralising and judgemental. Our divisions don't help."

He has never been afraid to criticise the Church of England, for being "too monochrome" and for getting bogged down in bureaucracy. "When the last trumpet shall sound, a commission will be set up on the significance of the trumpet, the financial implications of that trumpet, and for a report to come back in three years' time," he once said.

And he has no patience with different factions of the Church fighting over issues such as homosexuality. "I am driven to exasperation when Christians do not disagree well and Christianly," he says.

Sentamu hopes to use his promotion to York to provide a credible voice for the Church. "The Church of England has lost some of its wonder of the majesty and grace and love of God. For me, the gospel is such good news," he says."People today are more prosperous than ever, but no happier. This is a golden opportunity to reconnect imaginatively with people."

This is what he tried to do in Birmingham, where his sense of what mattered to ordinary people enabled him to win the hearts of much of the population, whether or not they were interested in the Church. A few months into his tenure, Charlene Ellis and Letisha Shakespeare were shot outside a hairdresser's shop in Aston. Sentamu was on the scene the next day: he walked the streets of Aston, led a vigil in memory of the girls, and was the first to have his hair cut when the salon reopened.

When the police investigation drew a blank, he published his home number so that any witnesses who were too frightened to speak to the police could contact him. He fielded 200 enquiries, and earlier this year four men were convicted of murder. Since then he has spearheaded a campaign against gun crime and gang culture in partnership with the other community leaders. More recently there were disturbances in the city, based on apparently unsubstantiated rumours of a rape. Sentamu says that exactly what happened is still unclear, but he has plans to meet the families involved.

In the same way, as soon as news of the impending collapse of MG Rover emerged, Sentamu requested a meeting with the management of the Birmingham car manufacturer, and publicly declared his intention to buy a Rover 75 because it was a well-designed and well-built car that would serve him for many years. And in 2004 he took out a full-colour advertisement in the Evening Mail calling on the people not to let extremists win seats in the local and Euro elections through apathy ("For God's sake Birmingham, use your vote"). No BNP or far-right candidates won seats. Another cause close to his heart is the Make Poverty History campaign. Last year he was invited by the Christian Socialist Movement to preach at the opening service of the Labour Party Conference, where he spoke on trade justice.

This grasp of ordinary local concerns may explain why Sentamu's admirers are drawn from other faiths as well as Christianity. Dr Mohammed Naseem, Chairman of Birmingham Central Mosque, calls him "very human, down to earth, and a friend of the common man", while Rabbi Leonard Tann, minister of Singers Hill Synagogue, praises him for having "held out the hand of friendship".

As Carl Chinn, Professor of Community History at the University of Birmingham, puts it: "He is able to talk to people of different kinds of beliefs, backgrounds and attitudes, partly because he has suffered so much f himself. He has made a massive effort to reach out to marginalised people, whether or not they are religious."

Sentamu is also well-known for his generosity: he gives away 20 per cent of his income, and entertains generously. He is a renowned cook (taught by his mother when he was ill as a child) and asked for a kitchen as his luxury on Desert Island Discs. He lists as his other interests music, reading, athletics and rugby. He also seems to have limitless energy, not only working extremely hard, but rising early every day to go to the gym before immersing himself in prayer.

At the heart of all he does, he says, is his prayer life. "Everything that I have ever fought for has come out of my deep sense of God," he says. "I never take up causes because they need to be taken up: I take them up because they have come out of a wrestling with God. Take the Iraq War: I wrestled with that, and came to my conclusions in prayer, so that no amount of persuading was going to change my mind. But we are not here to pursue issues and agendas, however important they might be. We are here to live and celebrate the good news of God."

Sentamu says he will be sorry to leave Birmingham. He is leaving a job he had expected to do for 10 years after just three. Now he and Margaret - who also works for the Church of England, helping to select future clergy - are exchanging their comfortable home in the leafy suburb of Harborne for the austere medieval palace of Bishopsthorpe. (Their children, Grace and Geoffrey, have both left home.) It's all a long way from Africa.

When he moves to York, his first priority will be to meet people. "I hope to find friends who will help me become the person I am trying to become. I have already written to say, 'Please let me know when I get things wrong.' I am looking forward to getting to know the people of Yorkshire." He grins. "I'm told they are straight talkers, so we are bound to get on."

He doesn't want, ultimately, to be remembered only for being the first black Archbishop of York. "I can't jump out my skin - I'm aware of that," he says. "But I'd like to be thought of as someone who made the Church accessible to everybody, particularly young people. As someone who brought the fun back. If I can contribute to the wellbeing of this great nation, I'll be very grateful. Abraham Lincoln said that wherever he found a weed, he'd plant a flower. I want to do the same thing."