Is there a new brand of violent extremism that is identifiably different from all forms of militancy that have gone before? The question is prompted by the shocking and self-publicised brutality of the group calling itself Islamic State. These groups provoke worldwide revulsion, but is force the only possible response? Hardtalk speaks to Giandomenico Picco, the former UN envoy who risked his life to negotiate the release of western hostages in Lebanon.