Leading article: We have learnt much about this plot, but little of it is consoling

There is no point in government agencies collecting information on suspects if they do not use it

When four bombs were detonated nine days ago within a mile of King's Cross, the intention was apparently to ignite a burning crucifix in the capital - north, south, east and west. And it was with the gnarled wreckage of three Underground trains and a double-decker bus that the police investigation began. With almost breath-taking speed, however, it has now escalated from these intensely local beginnings north to Luton and Leeds, west to Aylesbury and far beyond our shores, to the United States, to Egypt and Pakistan.

The latest stage in this improbably fast-moving investigation was the arrest in Cairo yesterday of a former chemistry student at Leeds university. He reportedly rented a house that has been linked to the presumed bombers. What more graphic illustration could there be of the challenge that Islamic fundamentalist terrorism presents? Even as the advanced economies of the world are trying to get to grips with globalisation, those with malign intent are able to exploit the ease of communications and travel for their own destructive ends.

It is appropriate here to compliment the police on the effectiveness of their operations so far. Many police investigations are no doubt completed expeditiously, but it is the failures that so often command attention - failures that reflect clumsiness, bungling and delay. We obviously know nothing like the whole truth about this investigation; the police and intelligence services commonly know more than they can disclose. But what we do know shows the police in a positive and professional light. One week ago, few would have hazarded that we would know as much as we now do about the bombings and those who perpetrated them.

The trouble is that very little of what we have learnt is in the slightest degree consoling. We have learnt that there were, and probably are, young men born and educated in this country who are ready to die as suicide bombers. Some were blameless family men prepared to lay down their lives for their interpretation of Islam. We have learnt of seemingly moderate men converted almost overnight to fanaticism, of youths in their teens carrying rucksacks of explosives, of a conscientious teaching assistant who calmly set out to kill. And we have learnt that it is possible, with the requisite expertise, to produce tubs of explosives from widely available ingredients without anyone noticing.

No less disturbingly, we have learnt of the gap that exists between the information that the authorities have collected and their will, or capacity, to act on it. Thus suspect individuals are known to arrive in this country, but are apparently not always tracked until it is too late. This is no plea for the panicked application of illiberal measures, but an observation that there is no point in government agencies collecting pertinent information if they do not use it.

The implications - domestic and international - of what we now know are not amenable to easy solutions. The dual approach called for by political and police leaders - a ban on entry to Britain for individuals likely to stir up religious intolerance, and more awareness and vigilance in the Muslim population about those who might be tempted into extremism - is a sensible, if overdue, start. And it is gratifying that, according to the Metropolitan Police Commissioner, the rate of racial attacks since the bombings has actually been lower than it was before. But there is no room for complacency. The hidden lives laid bare by this painstaking investigation show just how much ground there is to be made up.