But perhaps the most disquieting explanation for the ubiquity of the term is that it tells us something we want to believe. Yes, the terrorist threat now appears much more amorphous and unpredictable than ever before. At the same time, the idea that terrorists operate alone allows us to break the link between an act of violence and its ideological hinterland. It implies that the responsibility for an individual's violent extremism lies solely with the individual themselves.

The truth is much more disturbing. Terrorism is not something you do by yourself, it is highly social. People become interested in ideas, ideologies and activities, even appalling ones, because other people are interested in them.

The myth of the 'lone wolf' terrorist