When Donald Reeves, then Rector of St James’s Church, Piccadilly, was told that Margaret Thatcher had described him as “a very dangerous man”, he remembers being “rather pleased . . . it felt like a natural title”. With it he became part of the prominent Anglican tradition of “troublesome priests”, apt to turn their critical fire not only on the world around them but also on the Church that employs them.

And yet the man who enjoyed excoriating Thatcherite political views and episcopal complacency in the 1980s, emphasises his role these days as peacemaker rather than as trouble- maker. Through the Soul of Europe project that he co-directs, Reeves spends much time in the Balkans, attempting to build durable trust between communities only nominally at peace after terrible conflicts.

He is currently most engaged in Kosovo, talking to local Serbs and Albanians, seeking to “dismantle the fear each has of the other” and to break down the isolation of minorities — in this case the Serbs, and their ancient religious institutions, living under armed guard.

This follows many years’ engagement in Bosnia. There was support for the rebuilding of the famous Ferhadija mosque in Banja Luka, destroyed as Yugoslavia broke violently apart in the early 1990s. And in one particularly intense project, described with his colleague Peter Pelz in a book, The White House, Reeves spent years trying to create a memorial and place of reconciliation at a mine at Omarska near Prijedor, where Bosnian Muslims and Croats were tortured and murdered by Serbs in 1992.

Progress was uneven and inconclusive, as Reeves and his colleagues experienced how deeply rooted was the mutual suspicion and resentment of communities where, within such recent memory, co-existence had been replaced more or less overnight by murderous hatred. They had to listen patiently to “raw memories” and accept that there could be “no short cuts, no quick fixes”.

But persuading anyone from the various communities to engage at all was an achievement in itself, a crucial first step in peace-building that others had failed to try. He is scathing about the official peacekeepers, the cynical UN and EU bureaucrats “with their expat salaries and weekends in Vienna” who feel two years in Bosnia is good for their CV.

While Reeves speaks eloquently of the need for patience with people, his experience of large institutions — especially the Church of England — has never prompted a patient response. After a non-religious upbringing, studies at Cambridge and a job with the British Council in Lebanon, his entry into the Church of England was characteristically troubled. After an initial visit to the respected Cuddesdon theological college, he recalls in his memoirs, he said to himself: “If that’s Christianity, give me measles!”

Eventually he did train for ordination, but struggled to find his vocation in parish life. “The clergy don’t allow people to grow up,” he laments. “They treat them as if they were children.” However, early-1960s Maidstone was not ready for his iconoclastic version of the Nativity play, complete with disruptive teddy boys.

Inspired by several months working with religious groups and community activists in Chicago, he returned to work on the St Helier estate in South London. He sensed that locals were initially resisting his plans because “we were a colonial outpost, financed and sent by something called the Church of England”. But the sense of “powerlessness” of residents was challenged with a vigorous programme of community action, notably campaigning for patients’ rights as healthcare moved towards a more market-based system.

Reeves had already become a popular clergyman with the media, and enjoyed staging eye-catching cultural and other events. But it was his next appointment, to be vicar of St James’s Church in Piccadilly in 1980, that would really make his name. It was not, at first, an auspicious place, known for society weddings but with little evidence of a congregation rooted in the community: “On my arrival,” he said, “I could see no justification for keeping the church open.”

But gradually he turned it into a thriving institution, closely linked to locals, rich and poor, and, above all, a place for the exploration of ideas.

“Jesus wasn’t exactly into garden parties, He was regarded as a nuisance,” Reeves says. “The churches shouldn’t be creating little managers of sectarian communities but should be places of dissent.” His own dissenting challenge to Thatcherism was overt. He sparked lively debate by preaching against the invasion of the Falklands, and he helped the miners’ wives during their husbands’ bitter strike. But debate across boundaries was encouraged — invited speakers included Norman Tebbit as well as Tony Benn, non-believers as well as believers. And, in anticipation of later work in the Balkans, he began to explore the idea of peace-building, inviting Chinese and Russian visitors. Bishop Trevor Huddleston, a veteran campaigner against apartheid, who lived in the St James’s vicarage for many years, was another significant influence.

The Anglican hierarchy never seemed sure what to make of Reeves. He says he once had episcopal ambitions, trying on a mitre when chaplain to Mervyn Stockwood, Bishop of Southwark, “but I didn’t look right in it”. Yet a lack of recognition by the Church clearly still rankles. As he prepared to leave Piccadilly he recalls meeting the Bishop of London, who commented merely: “I won’t stand in your way — that’s bishop-speak for ‘you’re on you own, sunshine’.”

Were he a bishop now, Reeves says, he would urge the Church to stop selling off its vicarages, which he sees as valuable community centres, and to end its divisive obsession with issues of gender and sexuality. They involve important issues of justice but hardly seem so crucial when he considers, for example, what his friends in the Balkans have been through.

Imagination is the word that Reeves uses with most enthusiasm to summarise his work and belief, “the view that there is always something new waiting to be born” — whether in a London parish or a Bosnian town. “And imagination for me is the entry into religion,” he adds, an imagination that combines clarity about where society is and a vision of change. And when the imagination falters, when the depth of division in Kosovo or Bosnia seems too great, he retreats to play Bach on the organ, another great passion, where in the music he tries to master there is complexity, sometimes despair, but always, in the end, glorious resolution.

The Memoirs of a ‘Very Dangerous Man’ by Donald Reeves (Continuum, £16.99)