Londonistan, by Melanie Phillips

Fear and hysteria: these are the root emotions of terrorism. They are also the root emotions of the so-called war on terror. In July, in the run-up to the first anniversary of the 7 July bombings, al-Qa'ida released a video of one of the suicide bombers, Shehzad Tanweer. The aim was to terrify Londoners with the thought that last year's carnage was, in Tanweer's words, "only the beginning of a string of attacks".

That's exactly what champions of the war on terror also want us to believe. "Up to 16,000 British Muslims either are actively engaged in or support terrorist activity," Melanie Phillips writes in Londonistan, "while up to 3,000 are estimated to have passed through [al-Qa'ida] training camps, with several hundred thought to be primed to attack [the UK]." If you want fear and hysteria, nobody does it better than Phillips. What we are facing, she tells us, is a war of the worlds between Islam and the West. At stake is the very survival of Western civilisation.

Britain, however, remains in a state of denial. A combination of slack immigration controls, misguided multicultural policies and foolish attempts to reach out to moderate Muslims has allowed London to become "a global hub of the Islamic jihad": Londonistan. If Britain is to "halt the drift towards social suicide", it must repeal the Human Rights Act, establish special courts to deal with Islamic terrorists, ban not just groups that advocate terrorism but that promote "Islamisation", prosecute for treason anyone "advocating an Islamic takeover of the West", prevent Muslims from marrying spouses from the Indian subcontinent, and "teach Muslims what being a minority means". And all in the name of liberal democracy.

The events of 7 July certainly showed how easy it was to bring carnage to the streets of London. Paradoxically, they also showed why hysteria is misplaced. In Iraq, suicide bombers wreak devastation daily. Even Israel, with its unprecedented levels of security, is unable to prevent them. In Britain, so far, there has been one successful and one unsuccessful attempt. Terrible though that single event was, we should place it in context. If there really are 16,000 British Muslims actively engaged in terrorism, they seem very reluctant to show their hand.

The bombers' leader Mohammed Siddique Khan is thought to have visited training camps in Pakistan, though the official report into the bombings points out that these are often "little more than groups of people getting together on an ad hoc basis" and that there is no reason to believe the four men were part of an international network. The Tanweer video suggests that al-Qa'ida is eager to associate itself with the carnage but, according to the report, there is "no firm evidence" to corroborate its support, if any. No one in their communities had any inkling of what the four were about to do.

None of this is to deny that there is a wellspring of extremist attitudes within British Muslim communities. Only in a handful of cases, however, have such attitudes translated into terrorism. In any case, as Phillips herself argues, "many of these young men are not pious and barely set foot inside a mosque. Deeply secularised, they have little religious faith and adopt the habits of other slum-dwellers, including soccer and pop music, drugs, alcohol and casual sex." Aside from revealing an almost Victorian view of "slum dwellers", the argument also demolishes Phillips's insistence that contemporary terrorism springs from a clash of religious civilisations.

Phillips's criticisms of multiculturalism and of victim culture, her exposition of the spinelessness of policy-makers and her excoriation of the decadence of the left, deserve a hearing. But so immoderate is her assault on British culture that it is difficult to take it seriously. Britain, she believes, is locked into "a spiral of decadence, self-loathing and sentimentality", incapable of seeing that it is "setting itself up for immolation".

Gramsci's revolutionary aims of subverting Western culture and morality by "capturing all of society's institutions - schools, universities, churches, the media, the legal profession, the police, voluntary groups... have been accomplished to the letter". The pursuit of "human rights doctrine" has become "the principal cultural weapon to undermine the fundamental values of Western society". Why settle for rational argument when a paranoid rant will do, seems to be the attitude.

What is striking are not just the differences but also the similarities between Phillips's argument and those of the Islamists. Both insist that we are in a religious world war between the forces of good and evil. Both believe that only religion can help restrain decadent behaviour and establish a proper moral framework. Both abhor the growth of secular humanism. Both see Britain as "a debauched and disorderly culture of instant gratification, with disintegrating families, feral children and violence, squalor and vulgarity on the streets". Indeed, for all the ferocity of Phillips's assault on Islamism, she possesses considerable sympathy for the Muslim dilemma.

"British Muslims have concluded that the society that expects them to identify with it is a moral cesspit," she argues. "Is it any wonder... that they reject it?" Phillips might rage against the Islamists. The trouble is, she appears equally disgusted by what the Islamists want to destroy: secular modernity.

Kenan Malik's books include 'The Meaning of Race' (Palgrave Macmillan)