Editorial: Terrorism beyond imagination

The scale of the disaster British police say they prevented on Thursday takes terrorism to a new level. A plan to destroy perhaps 10 airliners in flight at the same time is more frightening in some respects than even the events of 9/11.

Four planes were commandeered on that day, flying from different cities in the United States. The conspiracy foiled by Scotland Yard was said to be aimed at many more aircraft due to fly from London to the United States. Had the plot succeeded, the date of 10/8 might have been the day air travel suffered its greatest blow. Ten planes from the same destination in a single day might have seemed to the individual traveller to increase the odds too much.

But the plot was foiled, and travellers might take some comfort from the view of experts that the larger a conspiracy becomes, the more likely it is to be discovered before it can do its deadly work. Britain's anti-terrorism unit is said to have had this one under watch for months, and police were able to move this week as soon as they heard or saw that the threat to public safety was imminent.

They made 24 arrests, and London airports were put on the highest state of alert and passengers were prevented from carrying more than personal effects on to aircraft. That restriction may be the main lasting legacy of the 10/8 emergency. These would-be terrorists were evidently intent on using liquid explosive in the passenger cabin to bring down the planes. The liquid could be carried in water bottles, babies' milk or other containers that air travellers commonly take on board.

There has been a suggestion that the bombs may even have been assembled from items carried on to the aircraft by several conspirators. If that is the case, security may require that all sorts of items, innocent on their own, may become routinely barred from cabin bags. Electronics and switching devices, cameras, cellphones, digital music players - all could be banned.

Much has still to be disclosed about the alleged crime, but its consequences may be felt for a long time.

What can be said, and ought to be said immediately, is that nothing can justify a crime such as this appears to be. It needs to be said because Britain's foreign policy is being offered by some commentators to explain the outrage. Britain's support for the United States in the Middle East may explain why it is a target but cannot ever justify actions of this kind.

Imagine, for example, that British foreign policy supported Hizbollah in the conflict in Lebanon? Would Jewish patriots be justified in seeking reprisals on civil airliners? Would anyone invoke their resentment as even an explanation for that? Some acts are too inhuman to be attributed to rational motives.

But nor should we rush to judgment as President Bush has done about an Islamic threat. Britain has a migrant population that has its own tensions, and harbours its own malcontents. It is probably counterproductive to see the same jihad behind every bush. If, as we are told, al Qaeda is more of an idea than an organisation, we run the risk of giving the idea more assistance than it can gain for itself.

Whatever the motivation of these would-be killers, the events of Thursday have reminded airlines and passengers of the need for vigilance. Airliners are clearly the favourite target of criminals bent on making as terrible a public impact as they can. Baggage checks and restrictions are probably going to become even more rigorous but after the close call this time, it would be crazy to complain.