The portrait of the modern terrorist is a compelling one, and there is shock and surprise that affluent, educated doctors should have been caught with their finger on the detonator. But a story in today’s Times, London, shows why we shouldn’t be:

A study of 172 al Qaida terrorists done four years ago by Marc Sageman, a forensic psychiatrist and former CIA case officer in Pakistan, found that 90 per cent came from a relatively stable, secure background.

Most were from middle-class or upper-class families, and were college educated professionals.

Sageman’s findings, published in 2004 in Understanding Terrorist Networks, led him to conclude that “most of these men were upwardly and geographically mobile”.

He wrote: “Because they were the best and brightest, they were sent abroad to study. They came from moderately religious, caring, middle-class families. They spoke three, four, five, six languages.”

Unlike the lone serial killer, these men functioned well in groups. Indeed, isolated in a foreign country, they depended on a close circle of friends who reinforced their beliefs.

“You could almost say that those least likely to cause harm individually are most likely to do so collectively,” Sageman wrote.

He said yesterday the existence of a terror plot involving doctors should surprise no one. “When you look at global jihad, you have three waves. The first were the companions of Osama bin Laden in the 1980s. The second were the best and brightest from West Asia, who became radicalised in the West. Many of them are engineers and physicians.

“The third are ‘home-grown’, who are second or third generation in the West, and they are less well-educated. Their average age is about 19 or 20, and there are more criminal elements there,” Sageman said.

Ask Sageman to name two likely professions for a second-wave terrorist and he selects “engineers and physicians”.

“What makes people like engineers or physicians try to work for the good of society is the same impulse that makes people sacrifice their lives for the sake of a community, (in this instance) the ummah (the global community of Muslims),” he said.

“Engineers and physicians are far more active in their everyday lives, trying to do things. They’re far more action-oriented than, say, lawyers. You don’t find many lawyers, but you find a lot of engineers and physicians.”

Read the full story here: Profile of a modern militant