Giles Fraser: Enough is enough. The extremists must be confronted

The Church of England had a pretty embarrassing start. For despite the fact that the Pope dubbed him the Defender of the Faith, Henry VIII's libido proved stronger than his commitment to Rome – so he slipstreamed the Reformation in order to warm his bed with a younger, prettier wife. So far, so shoddy. Yet, over time, what was cobbled together proved far greater than such ignominious beginnings might suggest. For the special genius of the Church of England was that it embraced a huge diversity of theological opinion. The idea was that we might be united by common worship rather than divided by doctrinaire argument. So why now, after hundreds of years, does this settlement seem under threat as never before?

The Church of England is fundamentally a theological peace treaty. As the Reformation plunged continental Europe into an ideological bloodbath, with Catholics and Protestants murdering each other by the million, England created a church that made the most remarkable claim for itself: both Catholic and Protestant. Sick of religious warfare, it invented the original big tent philosophy. Those of widely different philosophies could kneel together and worship God through the appropriately named Book of Common Prayer.

It was a pragmatic arrangement that came to shape our national character. The English didn't do doctrinal dispute, we frowned on the public exploration of ideological differences characteristic of those hot-headed Continentals. Instead, we agreed to differ and muddled along. We became the world's natural compromisers.

Sure, the Church of England gained a reputation for not believing in anything and being shy in speaking about things that really mattered. But it was a brilliant way of creating an inclusive church. The parish church was to be a place where, under God, the English would find an oddly workable unity.

Two things have undermined this vision: the British Empire and the internet. In the days of the Empire, missionaries from the English church made faith our most successful export. Global Christianity mushroomed in the 20th century, with Anglicanism leading the way. There are now 77 million Anglicans. But what did not get exported was the very idea of Anglicanism as a peace treaty. Transplanted into different soil, Anglicanism grew hotter and more ideological, re-exposing deep theological fissures between believers that the C of E had agreed to set aside for the greater good. With the growth in communications technology, these differences could no longer be hidden.

Liberals were horrified to discover that some Anglicans were little more than fundamentalists in vestments; conservatives were horrified to discover that some Anglicans had gone native with secular humanism. Gay sex started it all. And the more the headlines rolled in, the more the cracks widened.

In fact, the fight over homosexuality exposed a darker side to the English reticence to confront difference head-on. We all knew there were loads of gay vicars; we all knew there were many gay bishops too – but it was a form of knowledge communicated in nods, winks and church code. But the spirit of "don't ask, don't tell" kept many of them stuck in the church closet. It took an American bishop first to be open about having a partner of the same sex. Gene Robinson's crime was his honesty. Likewise, the idea that the gay "marriage" that recently took place in St Bartholomew's church was a first is simply not the case. There have been hundreds of such weddings. It's just that they have been – and what a very English word this is – discreet.

But all that is over. The conservatives have decided that they can exploit the deep homophobia of many African Christians in order to stage a coup for the soul of the church. Suddenly, we are once again fighting the unresolved battles of the Reformation, with narrow-minded puritans seeking to impose their joyless and claustrophobic world-view on the rest of the church. The newly formed Federation of Confessing Anglicans (Foca) is seeking bridgeheads in wealthy evangelical parishes and the English ecclesiological peace treaty lies in tatters. All eyes now turn to Rowan Williams, the Archbishop of Canterbury. Is there anything he can do about these Focas?

His track record isn't all that encouraging. Since this crisis began, Dr Williams has been bending over backwards to accommodate evangelical demands. Despite his progressive instincts, he reversed his support for the gay cleric Jeffrey John becoming a bishop and then decided that he would not invite Bishop Gene Robinson to the forthcoming Lambeth conference. Time and again, the Archbishop has given in to conservative ultimatums in the search for unity. And all that happens is that they come back for more.

A traditionally inclusive church like the C of E is especially vulnerable to infiltration by extremists. For the whole point of being inclusive is that all are welcome. It's a natural openness that is currently being exploited by those who have no love in their heart for the very inclusivity that allows them in in the first place. Even more so than the Labour Party in the 1970s, the English church is vulnerable to entryism. If fundamentalist Christianity were allowed to take over the Church of England, it would gain unprecedented access to national government through its role as the established church. The prospect of a state church, determined to convert Muslims, should set off huge flashing red lights in every corridor of power. In America, the separation of church and state creates a firewall between fundamentalist religion and state power. We have no such protection.

Rowan Williams is a good and holy man with an impossible job. He has a deep care for the worldwide church, especially in the poorer parts of Africa. But the current crisis needs him to care more about the condition of the Church of England. The open space that is the traditional mark of the English church is being undermined by a determined minority of well-funded extremists. It is time for him to fight back.

Reverend Dr Giles Fraser is vicar of Putney