Everybody who has shown, at sometime, an interest in extremist ideas, is not a terrorist nor likely to become one. A lot of us went through a rebellious phase in our youth and dabbled in all kinds of extreme left and right political or religious groups, more out of curiosity than commitment. We do not know whether we were noted and our names put on a list at the time. But, for example, there is a big difference between being concerned about animal rights and attend a hunt saboteurs meetingjoining the groups that physically attacked researchers and companies involved in animal experiments
The problem is knowing which of those outer circle dabblers will gravitate to the centre and how fast.
It is clear from the number of terrorist attacks that didn't happen because they were nipped in the bu - and we tend to forget about those, that our police and intelligence services are generally up to the mark and successful, but inevitably there will be some who slip through, especially with low tech attacks like that at the weekend.
It only needs 3 disaffected young men, with no history of active extremism, to psych each other up in a cafe over a coffee, hire a van and buy some knives or even a gun for there to be an atrocity.
