The cause of this is driven by the convergence of the Internet/Social Media, and freedom of movement of people and of goods. i.e. Guns and explosive materials.
The internet is 'impossible' to control, but is a reasonable source of intelligence.
Freedom of movement is controllable but needs investment and manpower. I'm afraid our politicians and the EC brigade don't seem to have the will to deal with this yet.
People movement would be easier to block than movement of freight.
But then there would be a huge cost to airlines and shipping companies - with further consequences.
