It is three years since the Madrid train bombings - the first Islamist terror attack staged in Europe - and thus an appropriate moment to evaluate Europe's experience with al-Qaeda since that dark day.
Madrid was a marker in the history of radical Islamist terror, and a catalyst for change in European policy towards global terrorism. It represented the first tangible proof of a new form of radical Islamist terrorism.
Across the continent, states that had not felt al-Qaeda was their problem now had to reassess that assumption. Cross-European co-operation in counter-terror and intelligence work, which before had been surprisingly limited, quickly became a top priority.
With the trial of the suspects under way, the attacks continue to be an open sore in Spanish political and social life. In particular, the role of al-Qaeda in the attacks has become an issue for scrutiny, debate and conspir- acy theories.
Some right-wing Spanish politi- cians and media outlets continue to champion the theory that the attacks were a grand conspiracy between Spanish socialists, national and foreign agents, and Basque separa- tists.
In less conspiratorial terms, this general debate has become promin- ent in the European and international counterterrorism community, as the media and the public - after every attack and broken plot - demand to know 'was this the work of al-Qaeda'?
The question is increasingly difficult to answer, however, in part because Osama bin Laden's group does not exist as a cohesive, centrally structured organisation. It remains a key ideological inspirer, and tries to exert as strong an operational influe- nce as possible. But as the years pass, its attacks and cell structures are increasingly the work of the localised, more independent adaptations of the al-Qaeda family.