It’s a curious boast, but the black cleric appointed last week to the second-highest office in the Church of England takes pride in having sent innocent people to jail as a young magistrate under Idi Amin, the Ugandan tyrant. It was a ploy by John Sentamu, Downing Street’s choice as Archbishop of York, to save the accused from summary execution.

The 56-year-old primate has explained that he was acting in the spirit of Oskar Schindler, the German businessman who saved hundreds of Jews from the Nazis. His own moral dilemma occurred among the victimised people of Gulu in northwest Uganda during the early 1970s.

Knowing that the evidence against 10 innocent people was insufficient to justify a trial, Sentamu jailed them on remand, convinced that they would be killed by Amin’s thugs if they were freed.

Asked later about the ethics of his actions, Sentamu said his Christian faith had guided him: “Justice is often not just innocent or guilty, justice is often doing what is right.” The accused were later released and fled to other countries. Sentamu was not so lucky, falling into the regime’s clutches before escaping to Britain.

The gap-toothed Bishop of Birmingham is a popular and outspoken figure who has fought against gun crime in the Midlands and tried to rally people behind MG Rover, the troubled car maker, by placing an order for a Rover 75 saloon.

He is married to Margaret, a Church House official, and they have two grown-up children, Grace and Geoffrey. As a guest on Desert Island Discs in 2003, his favourite records included What a Wonderful World by Louis Armstrong and O Holy Night by the Welsh singer Aled Jones. His chosen luxury was a kitchen — cooking and music being his main interests, along with rugby and football.

Only two facts count against him: his inability to delegate and his staccato speech, although his witty contributions to Synod debates always empty the tea rooms around Church House.

His appointment has prompted much speculation. There was no obvious front-runner and Sentamu was an outsider. The House of Bishops would have preferred an administrator such as John Gladwin, the Bishop of Chelmsford, while Rowan Williams, the Archbishop of Canterbury, maintained a neutral stance.

Sentamu was one of two names from a shortlist of five drawn up by the Crown Nominations Commission submitted to Tony Blair. Some close observers believe Downing Street pushed for Sentamu, who won respect when he advised the prime minister’s social exclusion team. It would not be the first time that Blair exercised his prerogative over the Church of England in an appointment.

Like Williams, Sentamu represents a two-edged sword to Downing Street. In 2003, a year after his appointment as Bishop of Birmingham, he led church protests against the war in Iraq, denouncing the invasion as having “no moral basis”. Yet he stoutly defended Blair against Michael Howard’s accusations of lying about Iraq, which he characterised as “not acceptable in a civilised country”. Ignoring the potential downside, Blair told colleagues he wanted “ men of vision” leading the church.

But by elevating a radical African cleric who has campaigned tirelessly against racism, Blair’s timing could not have been better. It demonstrates the seriousness of his commitment to Africa at the G8 summit next month. It may also stifle an increasingly nasty row within the Anglican church.

African anger with the northern churches’ stance on gay priests is expected to erupt at this week’s meeting in Nottingham of the Anglicans’ executive body, the Anglican consultative council. In Sentamu, a mild evangelical who mirrors the Africans’ conservatism on church doctrine, they may recognise a kindred spirit.

More important, perhaps, Sentamu has no patience with the internecine battles that constantly divide the Anglicans but have little relevance to the outside world. According to an insider: “He says, ‘How can you squabble about gay priests when half of Africa is dying of Aids?’ ” With withering eloquence, Sentamu said of church 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 10 years’ time.”