The British security service, MI5, has concluded an exhaustive investigation into domestic terrorism and says that it's impossible to draw up a profile of a "typical" terrorist:
The sophisticated analysis, based on hundreds of case studies by the security service, says there is no single pathway to violent extremism.
....They are mostly British nationals, not illegal immigrants and, far from being Islamist fundamentalists, most are religious novices. Nor, the analysis says, are they "mad and bad".
Those over 30 are just as likely to have a wife and children as to be loners with no ties, the research shows.
The security service also plays down the importance of radical extremist clerics, saying their influence in radicalising British terrorists has moved into the background in recent years.
....Far from being religious zealots, a large number of those involved in terrorism do not practise their faith regularly. Many lack religious literacy and could actually be regarded as religious novices. Very few have been brought up in strongly religious households, and there is a higher than average proportion of converts. Some are involved in drug-taking, drinking alcohol and visiting prostitutes. MI5 says there is evidence that a well-established religious identity actually protects against violent radicalisation.
Is this bad news? Hard to say. If MI5 had identified a decent profile (or a set of profiles), that would have led inevitably to targeting of often innocent communities. But the lack of a profile will almost inevitably lead to authorities spreading an ever-wider surveillance net. Hobson's choice.