In the late 13th century with the Catholic church in crisis, the reputation of the papacy at a low ebb and no obvious candidate to take over as Pope, the cardinals sent for Pietro di Morrone, a Benedictine hermit. Morrone, unworldly and humble, did not want the job, even attempting to flee when it was pressed upon him. But he became Pope Celestine V, his claim to fame being a decree giving popes the right to abdicate the papacy, which after a few years he promptly did.

When Rowan Williams was enthroned as Archbishop of Canterbury five years ago, he was no hermit. Even his admirers would concede, however, that his background as an academic theologian — he became Oxford University’s youngest professor in the 1980s — had left him rather unworldly. His champions believed that his mild-mannered, thoughtful but determined approach was exactly right for an Anglican church facing deep schisms over homosexuality and the ordination of women.

Five years later they must be disappointed. The schisms in the church have deepened, exacerbated by the archbishop’s support for women bishops, a red rag to conservative Anglicans. His handling of the even more divisive issue of gay clergy, which got off to a poor start with the appointment, then withdrawal, of Jeffrey John as Bishop of Reading, has been weak. Instead of leadership, there has been woolliness. Couple that with a style that could have been designed to empty the pews and the church has a problem.

While his time in office has not been good for the church, which had to defend itself recently over figures showing more Catholics attending regular Sunday worship in Britain than Anglicans, the archbishop has often entered the political debate, attacking the Iraq war and “humanity’s selfishness” over the environment. Never before, though, has he created such a storm as with last week’s comments on sharia (Islamic law).

When two members of the General Synod call on him to step down, when David Blunkett, the former home secretary, describes his remarks as “dangerous”, when Downing Street slaps him down and the primate of Nigeria accuses him of “most disturbing and most unfortunate” comments, you know that he has put his foot in it. What was he thinking of, venturing into this territory and saying it “seems unavoidable” that some aspects of sharia will be adopted in Britain?

He would say he was trying to correct common British misunderstandings about sharia. It is not, as he put it, “all the darkest images of Islam”, such as the repression of women, stoning, flogging and mutilation. His second aim appears to have been to make a plea for “a higher level of attention to religious identity and communal rights” to be embodied in the law more generally. But the archbishop and his advisers must have known that most people would not have spotted such subtleties. He should have anticipated, in particular, concerns over safeguards for women deprived of basic rights under several forms of sharia. Many Christians were disturbed by what appeared to be a surrender to multiculturalism. Moderate Muslims saw his remarks as feeding anti-Muslim prejudice. If his aim was to help to achieve greater social cohesion, he failed.

The government was quick to slap down Dr Williams but its record is far from unblemished. Why, if sharia is not for these shores, does the benefits system recognise polygamy among Muslims? Where is the debate about matters of concern such as the practice of many Muslims in Britain of marrying first cousins, leading to a high proportion of babies with birth defects?

People are alarmed by the notion of “no go” areas for non-Muslims and about the erosion of traditional British values. These are legitimate topics for a public debate but the archbishop is not the man to lead it. It would be better for him to abandon Lambeth Palace and return to academia to allow a shrewder figure to lead the church.