The nature of the terrorist threat to which western democracies are exposed is mutating. That much was suspected after the Madrid train bombings in March 2004. The investigation into the London bombings has brought the lesson home. By most accounts, the centrally controlled al-Qaeda of September 11 2001 is no more, while the contours of the threat that has replaced it are still being sketched out.

This realisation has led governments in Europe and the US to re-evaluate the counter-terrorism measures at their disposal. In many cases, they are casting a glance over the fence at how their neighbours are coping, and inviting comparisons, most notably with the UK. This is a natural and appropriate response. But there is also a temptation for governments to "look busy" when they sense public concern. The measures being introduced or countenanced since the London bombings therefore deserve particularly intense scrutiny.