Less than a week ago London had an extraordinarily lucky escape when two car bombs failed to explode in the centre of the city. Another terrorist attack at Glasgow airport proved equally futile. Terrorist incompetence helped the police detain eight suspects in swift succession. But the incidents underlined a more disturbing reality: that in nearly six years since the terrorist attacks of 9/11, the phenomenon of militant Islamism disseminated by al-Qaeda has not been tamed. Rather, it has spread to new groups and new parts of the world.

Law enforcement in Europe and America has certainly improved, as have intelligence gathering and the exchange of information about jihadi groups. That has been instrumental in thwarting some attacks. But as the current FT series on al-Qaeda reveals, although the organisation of the movement has been severely curtailed, its spread as an ideology, and as a global brand of totalitarian jihadism, has not. The internet spreads its words. It is a message that resonates as much with well-educated and relatively prosperous young Muslims as with the miserable and dispossessed.