Mark Coles profiles Russian Foreign Minister Sergei Lavrov, a key figure in the Syria crisis. Has this chain-smoking, vodka-loving diplomat managed to restore Russian power?

Those who've dealt with him tell us just why he's such a formidable opponent, and how he survived the collapse of the Soviet Union to put Russian diplomacy back at the centre of world affairs.

Producers: Chris Bowlby and Smita Patel.