Does it follow automatically that if someone murders many innocent people in cold blood, as Anders Breivik did, they must be insane?

Anders Breivik "was a terrorist, he was not just an isolated madman" says Maajid Nawaz, co-founder the think tank Quilliam which studies Islamic extremism.

Speaking to John Humphrys, Mr Nawaz said it was "dangerous" to use the madness label because it suggested that someone is "not responsible" for their actions.

"It is relatively uncommon" in cases such as that of Anders Breivik, to find someone with a psychotic disorder, agreed Professor Andrew Silke, author of The Psychology of Counter-Terrorism.

Treating Anders Breivik as "deviant", he argued, makes it possible to ignore the wider social implications of his extremism.

"What if [people like Anders Breivik] are not mad? Then you have to deal with the problem in a different way."

Get in touch with Today via email , Twitter or Facebook or text us on 84844.