When Rowan Williams was appointed Archbishop of Canterbury almost exactly six years ago, one Church of England bishop is said to have rolled his eyes heavenwards and murmured: "God save us from a holy bishop."

That was not the general view at the time. Williams's appointment as the 104th archbishop since St Augustine was broadly welcomed, both within the church and even from the massed choir of leader-writers and commentators, as an inspirational one.

At last, after decades of decline, dismay and disillusionment under dull, wily or managerial primates, there was to be a leader who was not only an intellectually brilliant theologian, but someone who was a wonderful speaker, almost ostentatiously spiritual, a deep thinker and self-evidently holy.

If anyone could reverse the decline and lead the renewal of the established church, Williams was that man. He might even be its last chance.

At the time, the anonymous bishop's remarks seemed out of joint. But now many are not so sure whether holiness is enough and Williams can handle the crisis tearing Anglicanism apart.

As he prepares to welcome the bishops of the worldwide Anglican communion to their once-a-decade meeting at the Lambeth conference tomorrow, his first as Archbishop of Canterbury, Williams knows that as many as a quarter will not turn up and that there are open challenges to his leadership of the third largest Christian denomination, both from across the world and within the Church of England.

Last week, as the Anglican general synod in York overruled his advice to provide stronger safeguards for those opposed to women bishops - even though he himself is in favour of women in the episcopate - he sat with his head in his hands. Derided by conservatives, despaired of by progressives, his leadership flounders in division and dismay.

One archbishop from outside the church said: "There is an unholy alliance of Church of England dissidents and the disaffected. The potential for further disintegration is clear. Quite honestly, his personality and way of doing things are not geared for conflict diplomacy. He means well. He's a godly man, but he's theorising when what is needed is action.

"Is he the wrong person to deal with this? He looks for consensus where there is none and, when you listen to everyone, you end up losing sight of the plot. The gifts for which he was chosen are being stifled. It's a tragedy. I am sorry for a man who wants to do what's best but doesn't see it in terms of leadership. He has all the gifts to be a professor or an academic, but not an archbishop. What is needed is someone who can get their sleeves rolled up and provide some downright unintellectual leadership."

With the Anglican communion crumbling around his ears; with revolt among the remaining rump of high Anglo-Catholics over the church's palsied progress towards women bishops; with conservative evangelicals around the world in alliance with some African primates against any accommodation with gay people and with a fierce internecine struggle over authority and property in the sister American Episcopal church, Williams must wonder whether it wouldn't have been better to do what he considered as a student and become a Catholic instead.

As he shuts the double doors leading to his family's gloomy second-floor flat in Lambeth Palace, among its gothic battlements and surrounded by the high wall that once kept out the London mob, the archbishop must reflect on what on earth he has taken on. "He thinks it's horrible," says one close to him.

Even worse, he must ask himself whether he might be the last Archbishop of Canterbury to preside over the worldwide Anglican communion, which stretches across 164 countries in 38 church provinces and still claims to be the third largest Christian denomination. It notionally embraces 70 million followers, though as a third of those are English, of whom fewer than a million go to church in any given week, the number of true believers is much smaller and - as with many other denominations - sinking.

Power struggle

If this ever was a dispute about what the church thinks men get up to in bed together, or even, as evangelicals like to claim, about scriptural authority and obedience to the Bible, it now looks much more like a highly politicised power struggle for the soul of Anglicanism, with the archbishop stuck in the middle, trying to hold the show together.

Are they people of the Book, or people of the Spirit: governed by indelible words and rules laid down 2,000 years ago, or by the evolving spirit of Christian understanding in a changing world?

Some evangelicals are demanding a church within a church with their own disciplinary structures and self-appointed tests for orthodoxy; some archbishops claim loudly that the church is broken; others will not share communion - the fundamental test of fellowship - with those they deem unclean because of their liberalism towards gay people.

Although archbishops of Canterbury have only seen themselves as leading a truly international church in the last 50 years, just as the British empire evaporated, the office has always remained a central focus of Anglicanism. Part of the definition of being an Anglican is that you are in communion with Canterbury.

But now Anglicans are at each other's throats, seemingly obsessed to the exclusion of what might be thought rather more important matters of faith and Christian concerns, such as world poverty. Williams himself has come under almost continuous, virulent and often vicious attack from Anglicans who think of themselves as Christians. Is the game worth the candle? Is it worth all the effort to keep Anglicans singing from the same hymn sheet?

"There is a martyrdom complex there," says one senior cleric who has known the archbishop for many years. "He believes this is a cross he has to bear. I've heard him say it."

There is also concealed anger, according to another friend, a former primate. "He is exploding with anger ... He can hardly bear to hear the names of some of the bishops who are causing him grief."

And not only bishops. This is David Virtue, an American blogger of the spittle-flecked variety: "Williams puts collegiality ahead of gospel truth. That won't fly with these folk any more. The schism has already been caused by the liberals and pan-sexualists. If there is a break ... it is precisely because of the intransigence of the liberals and Affirming Catholics like Williams who want to change what revealed truth is.

"The post-colonial mentality of Williams and the Church of England hierarchs ... are appalling examples of xenophobia. The vast majority of the Anglican communion will no longer take it. They are done. Their leaders have tolerated the patronising tones of Williams long enough."

This is just the small change of daily abuse from Virtue and other online commentators and so far the reverse of truth or reason as to be risible. Although Anglicanism has gone through previous crises, this is the first to be fomented and exacerbated by the internet.

Not so long ago, it would have taken weeks to get a letter to Nigeria and then a response. Now, Peter Akinola, Archbishop of Abuja, one of the leaders of the conservative faction, a man who says homosexuals are worse than beasts, can be juiced up to outrage within minutes.

This was him at a meeting of conservative Anglicans in Jerusalem last month: "We must rescue what is left of the Church from the error of apostates ... we cannot dare not to allow ourselves and the millions we represent to be kept in a religious and spiritual dungeon ... We can no longer trust where some of our Christian leaders are taking us."

Not all African Anglicans think like Akinola. Njongo Ndungane, recently retired Archbishop of Cape Town, says: "There is a lack of charity, tolerance and magnanimity, a lack of listening and understanding, and Rowan has been taken advantage of. Our strength is unity but instead colleagues are focusing on the disintegration of the communion. They are fixated on one issue. It's a power-play going on."

Williams has tried hard to steer a middle course. It has not stopped him suffering regular abuse, more repeatedly, harshly and degradingly than most - he has had dog excrement in the post - but on a more concerted and organised scale than his predecessors.

He's meekly taken it too: "The trouble with Rowan," Richard Chartres, the Bishop of London, once boomed, "is he's too damn Christian towards these people."

Not that Williams has the united support of the English bishops. Factionalism is rife with ambitious men such as Rochester's Michael Nazir-Ali, overlooked when Williams was appointed and again when John Sentamu was made Archbishop of York, scarcely giving Williams his support. Nazir-Ali may be a darling of the rightwing press for saying rude things about the Islam of his forebears, but he is not collegiate, or broadly liked even by fellow evangelicals among his colleagues - some of whom regard him as arrogant and patronising.

Nazir-Ali was one of two English bishops to attend the Jerusalem gathering where he spoke in barely veiled terms about his disdain for the church leadership. He will boycott the Lambeth conference, 20 miles down the road from his diocese.

Conservative evangelicals in the C of E never liked Williams's appointment. From the start they harangued him as a heretic and false teacher, words which ring archaically in the 21st century even from men (it's always men) who go on to tell you seriously that the 17th-century Reformation still needs to be finished. Philip Jensen, dean of Sydney Cathedral and brother of the city's archbishop, Peter, who is one of the leaders of the insurgency, even called him a "theological prostitute".

Such men would not allow the Archbishop of Canterbury to preach anywhere near their pulpits lest he infect their congregations with falsehood.

What they don't like is that Williams has in his academic past suggested that sexually active, partnered gay people might actually have a part in church life. In a lecture in 1989, long before he became a bishop, while he was still Oxford's Lady Margaret professor of divinity, he said: "If we are afraid of facing the reality of same-sex love because it compels us to think through the processes of bodily desire and delight in their own right, perhaps we ought to be more cautious of appealing to scripture as legitimating only procreative heterosexuality."

Williams has never recanted his views. But he has also never been forgiven by gays and liberal Anglicans for forcing Jeffrey John, a celibate gay theologian, to stand down after he had previously agreed to his appointment as suffragan bishop of Reading in 1993.

The climbdown came following pressure from conservative evangelicals who enlisted support not only from bishops but from leaders such as Akinola. Williams, less than a year in office, thought the appointment would split the communion. It didn't help that the American diocese of New Hampshire was at the same time electing (in contrast to the church here, where soundings are taken and then prime ministers appoint and the Queen approves) a partnered gay bishop of its own, Gene Robinson - and he could not be forced to resign.

Five years on, the fury remains. Here's Marilyn McCord Adams, the American theologian who is Oxford's regius professor of divinity: "He has undermined us big time. He's not a good leader - he'd be better to be what he was before, a bishop in a small diocese.

"With its current attitudes to gays and women, what intelligent English person is going to think it is good to be part of the Church of England?"

Or Richard Kirker, leader of the Lesbian and Gay Christian Movement in Britain: "I wonder whether Rowan's desire to hold the communion together has been more important to him than making it clear where he stands. Leadership is about clarity of vision, not appeasing factions with irreconcilable differences. The evangelicals have never been in the compromise business. They've been indulged and emboldened."

Confused

The US and Canadian churches also feel confused and abandoned. Robinson's election was the excuse for some conservatives in the traditionally socially liberal Episcopal church to launch their attempt to dissociate themselves by setting up their own networks, supervised by province-breaking African bishops. The Africans have even started making some of the conservatives bishops in their own churches - Rwanda has nearly as many American bishops in its church as Rwandans - entirely against Anglican traditions of episcopal autonomy.

Liberal American bishops - many of them old friends of Williams, who knows the US well - have been baffled by his apparent unwillingness to understand their democratic polity. Although some who consecrated Robinson privately now say it was a mistake because it upset the rest of the communion so much, they insist that he was properly chosen and rightfully elected.

It exasperates them that the archbishop has spoken as though the Episcopal church is evenly divided, when actually its schism involves half a dozen dioceses out of 113, and that it took Williams four years to attend a meeting of the US bishops in New Orleans last September. By all accounts, they were distinctly unimpressed - and he and his staff were surprised to find that the Americans were serious and godly men and women, not the atheistic ogres painted by their opponents.

There are complaints on all sides about the calibre of the archbishop's staff - mediocre, indolent and out-of-touch, say many, preferring to keep their man walled up at Lambeth. But they can point to what happens when he gets loose, as with his much-criticised speech on incorporating aspects of sharia law into the English legal system.

Williams did not consult his staff before making the speech, otherwise they would have advised him to reword it. But he doesn't always listen to that sort of advice, from men less clever but more worldly then he is. There is still something of the don about him. He has lots of study time and last year, amid the Anglican crisis, took three months off in which he completed a 110,000-word book on Dostoevsky.

Admirable though such detachment is, it leaves an impression of drift, often dressed up as an example of his reflectiveness, allowing time for wounds to heal, for the greater good to prevail.

Actually, it may be just cluelessness. One former primate says: "I once asked Rowan what his strategy was. He twitched his eyebrows and said, 'There is no strategy.' That shocked me."

The crisis has just got worse, however, with the vacuum of leadership. Williams sometimes seems to bear the imprint of whoever last sat on him, translated as, in the words of Akinola, overheard chortling to colleagues at a primates' meeting: "He'll do what we tell him."

But Williams's supporters say this is deliberate: he doesn't "do" leadership like his predecessors: his is a collegiate, consensual approach.

Martyn Percy, principal of Ripon College Cuddesdon, the theological training college near Oxford, says: "He is deeply unpopular because he looks dithery and prevaricative, but the institution is woolly and thick-knit. He has this theological vision to hold all this together. Rowan is calling the church to account and sacrifice. There should be no reason to break apart: that would be failure. He's a priest and teacher, not a CEO."

Nevertheless the void has been filled by more determined and aggressive characters than he and disaffection is spreading. The recent meeting of evangelicals in London attracted far more attendees than the organisers expected.

Stupid

"It wasn't just the usual suspects," one evangelical English bishop said. "The church will have to take them more seriously, but the House of Bishops isn't ready to do that. He's lost the respect of liberal catholics over the gay issue and conservative evangelicals don't like him because they are too stupid to understand his theological nuances and think he isn't a proper Christian. History will judge Rowan to have been much more effective than people like to suggest. The Lambeth conference and the Anglican communion are busted flushes now, but that's not Rowan's fault for trying."

The insurgent coalition remains confused: American high church Catholics making convenient common cause with English, African and Australian evangelicals such as the Jensens who say they could never attend a high church mass.

They want their definition of Anglican orthodoxy imposed, but not by an archbishop with views such as Williams's. They insist they are not leaving, but that is possibly because they mostly have nowhere else to go. Anglicanism remains, in the old evangelical phrase, a convenient boat to fish from: outside the seas are dark and choppy. They would not have the status of the institution, its buildings or its resources.

Alister McGrath, one of the most respected moderate evangelical academics, said: "It is not Rowan's fault that he is left looking like King Canute. Big cultural forces are causing the church to split and what held it together in the past is no longer there. While there are undoubtedly theological issues, it is also profoundly political.

"Rowan has a very high view of unity and has worked hard, but it is not going to be enough. It is virtually impossible to achieve consensus and it is very difficult to exercise leadership in that context. Leadership is about more than finding consensus - you also have to map out the route that you believe to be right."

What is constantly overlooked is that the archbishop of Canterbury has purely symbolic influence, not power. He can't impose his will even on the Church of England, let alone the other provinces of the worldwide communion. What the position has is authority. What it has lost is respect.

CV

Background Born 1950, in Swansea, where his father was a mining engineer. Married to Jane, with whom he has two children, Rhiannon and Pip.

Education Christ's College, Cambridge, BA 1971, MA 1975. Wadham College, Oxford, PhD 1975.

Work Theology lecturer, College of the Resurrection, Mirfield, West Yorkshire 1975-77; ordained priest in 1978; canon theologian, Leicester Cathedral 1981-1982; dean and chaplain, Clare College, Cambridge 1984-1986; Lady Margaret professor of divinity, University of Oxford 1986-91; Bishop of Monmouth 1991-2002; Archbishop of Wales 1999-2002; elected as Archbishop of Canterbury in 2002.

Publications Prolific author and essayist on philosophy, theology and religious aesthetics. Recent work examines contemporary cultural and interfaith issues.

Recreations music, fiction, languages