Speaking on Sky News, Mr Johnson said: “In many ways the guys who did this kind of thing are very often at the fringes of criminality, lured into terrorism by very cynical and clever idealogues. In many ways they are vulnerable to all sorts of criminality.
“You have got to have a very tough security solution, to be absolutely determined to monitor these people, know where they are, know who they’re talking to.
“I’m not particularly interested in this civil liberties stuff when it comes to these people’s emails and mobile phone conversations. If they are a threat to our society then I want them properly listened to.
If someone’s a genuine threat then I want them listened to. Surveillance targeted at those the authorities have reason to believe pose a threat is fine, but we should not be engaging in mass surveillance of the general population, and that’s why I oppose the snooper’s charter.