"Many of us," he wrote, "have been working with Islamic leaders," and "the appearance of double standards inevitably diminishes the credibility of Western governments with the people of Iraq and with the Islamic world generally". The implication of the Archbishop's letter is that the world of Islam is entitled to be exacting because it shares Christendom's values and our tendency to criticise ourselves.

In fact, in all of his statements touching Islam (there have been oh so many), Rowan Williams suggests that it is just like Anglican Christianity or Reform Judaism, that it shares their fundamental hostility to imperialism and misrule, and would feel the same shame that "we" do, were it held responsible for prisons like Abu Ghraib, or human tragedies like the plight of the Palestinians.

Dr Williams's belief that Christendom and Islam are one was perhaps most apparent on December 21, 2003, when he condemned the detention of Muslim asylum-seekers who, the authorities believed, were planning atrocities against the Britain on whose mercy they had thrust themselves. "There is theological debate here which is real and deep," Williams said on that occasion of his relationship with Islam, "because we share some history and we can discuss it."

Can we discuss the fact that the Muslims here, all recent immigrants, enjoy rights - for instance to propagate their religion - that are unavailable to the Christians of the Muslim world? This is despite the fact that these Christians are the original inhabitants and rightful owners of almost every Muslim land, and behave with a humility quite unlike the menacing behaviour we have come to expect from the Muslims who have forced themselves on Christendom, a bullying ingratitude that culminates in a terrorist threat to their unconsulted hosts.

Dr Williams has nothing to say about this: but then, Christian passivity in the face of Muslim narcissism and aggression is nothing new. "The history we share" is that Mohammed enjoined his followers to spread Islam by the sword. After his death in 632, Muslim armies poured out of the Arabian peninsula (the only place to which Muslims are native, though even there Islam was imposed by force) and, unprovoked, attacked its neighbours.

Christian Egypt, Palestine, Syria, Iraq, Anatolia, Spain, the Balkans, the Maghreb and Sicily, as well as Buddhist central Asia, Zoroastrian Iran and Hindu India, all became "Muslim" by virtue of naked imperialism. The indigenous non-Muslims were either exterminated (the fate of the Christians of North Africa), or reduced to the status of third-class citizens in their own countries, their fate to this day.

The Crusades - for which the Pope has apologised to Islam (he did so again last week), rather as an old lady might apologise to a mugger for trying to retrieve her purse - were simply an attempt by medieval Christians to get their homelands back. Spain, Sicily, and parts of the Balkans were recovered. Palestine wasn't, though the Muslim colonisers there - who are no more "native" to the Holy Land than the European Jews who removed them - were largely ejected in 1948. It goes without saying that today's Muslims - who, unlike today's Westerners, are very proud of their history of imperialism - are highly indignant at being parted from this stolen property.

As the Pope's statement shows, Dr Williams's willingness to swallow the camel of Islam's treatment of others while straining at the gnat of Christendom's "sins" against Islam is traditional. What is unprecedented is the theological concession implicit in his remarks, ie that Islam is part of the Judaeo-Christian continuum. This idea naturally lends credence to the Muslim claim that Christ is not God, but just one in a line of Judaeo-Christian "prophets" whose "seal" is Mohammed, a claim which allows Islam to appropriate to itself the greater achievements of the Judaeo-Christian world.

As Councillor Fiyaz Mughal of Oxford wrote, in a letter to The Independent of Christmas Eve 2003 supporting Dr Williams, Christianity and Judaism are, to Muslims, "part of their own belief". And are thereby negated: for why bother to remain within Christianity or Judaism when the more "perfect" form of both is Islam? This presumptuous attitude to other faiths is so characteristic of Islam that the philosopher Konrad Elst has called it "jihad negationism". He has pointed out that its physical manifestation is Islam's practice of eradicating older religions by planting mosques on their holiest sites; for instance, the Babri mosque in Ayodhya, the birthplace, to Hindus, of Ram; and the Omar mosque on the platform of the Temple in Jerusalem, the Holy of Holies of the Jewish people for millennia.

The endorsement by Dr Williams of the idea of continuity between Christianity and Islam violates the teaching of every Church father since Muslim communities first appeared in the seventh century. These cite Christ's own warning that people would arrive in His wake claiming to bear a message from God superseding the Incarnation's: "Beware of false prophets. They come to you in sheep's clothing, but inwardly they are ferocious wolves. By their fruit you will recognise them."

The "fruit" of Islam is all around us: we can draw our own conclusions. It is felt in the presence of the Muslims who have fled to a thriving Christendom from the failure and horror of the Muslim world. (Would Muslims show a similar hospitality? It seems unlikely when they rail against the five million Jews who have settled in Israel, while gloating over the fact that 20 million Muslims in less than 30 years have inundated Europe.)

These immigrants seem not to realise that the need they feel to flee Islam negates everything they say in its favour, as well as rendering absurd their constant anti-Western diatribes. The Archbishop of Canterbury has no such excuse.

END