Leading article: The 'war' must be fought on British soil

It would have been more courageous of Tony Blair to have said he accepted that his Iraq policy had prompted passionate opposition among reasonable people and that it had also helped further to enrage people who were unreasonable. Some of these people may have already subscribed to the evil al-Qa'ida ideology, but others may have come to subscribe to it partly because of the war. And Britain's part in the war probably made London more of a target than it would otherwise have been.

Had Mr Blair conceded that much, he could then have enjoyed our full support to go on to say that it is simplistic and dangerous to ascribe the London bombings solely to his Iraq policy. This newspaper warned him publicly, as did the Joint Intelligence Committee in secret, that invading Iraq was likely to heighten the threat from international terrorism. But that is no longer the issue. Mr Blair is right that the ideology of al-Qa'ida is deep-rooted and would have had to be confronted whether or not we and the Americans invaded Iraq. In any case, British forces cannot now withdraw from Iraq. Having made our mistake, we have a solemn obligation to stand by the people of Iraq and to try to make the best of it.

The challenge that confronts us now is closer to home. What has changed over the past week is that we now know that the London bombers did not come from the Great Out There. If there are any consolations from the horror of 7 July, one of them might be that responsibility for our security lies mostly with us. Counter-terrorism is not primarily a matter of border controls, of asylum and immigration policy. The bombers were British. Their ideology has to be fought here, as well as abroad. On this, Mr Blair is on stronger ground. As a politician who has long had a better understanding of Islam than the average non-Muslim, he is well placed to lead that effort.

Needless to say there is no easy answer - no magic legislative bullet as the Home Secretary rightly said - to the question of how to pull up al-Qa'ida ideology by its roots. But it is already clear that there are some things that this struggle is not about. It is not about racism, isolation and poverty. The bombers do not seem to have suffered notably from discrimination, cultural exclusion or poor education. On the contrary, those brought up as Muslims seem to have turned to the ideology of violence partly as a reaction against the assimilation of Muslims into British culture.

It is also clear that choking off home-grown terrorism requires some changes that may be painful for some. Many Muslims are getting tired of "demands" that they repudiate the terrorists. Too bad. Roman Catholic leaders were rightly asked to disown IRA terrorism, even though the IRA was motivated by a secular ideology of national liberation. Muslims do have to confront the fact that their religion and their holy book are used by extremists to justify murder. They also have to face up to the reality of anti-Semitism among their number, and to double standards. Too many British Muslims are prepared to make excuses for the killing of Israeli civilians, even while they condemn the suicide bombers here. That is a failing, too, of some British liberals, and there are undoubtedly some awkward issues for non-Muslims to face as well. Non-Muslim liberals should not allow, for example, lazy notions of respecting cultural difference to slide into the toleration of intolerance.

The real war on terror needs to be fought, as we have always said, by means of police work and intelligence. That is not all. US and British foreign policy has been too often counter-productive, but it is not the main issue. Mr Blair is right at least in this: "In the end, it is by the power of argument, debate, true religious faith and true legitimate politics that we will defeat this threat."