Stephen Sackur speaks to Staffan de Mistura, the UN special envoy charged with trying to find a way out of the conflict in Syria. He has spent four decades trying to stem bloodshed by way of diplomacy but is Syria mission impossible?
(Photo: UN Special Envoy for Syria Staffan de Mistura attends a conference held by Catholic at the Vatican, 2016. Credit: Andrew Medichini/AP)
