Mikhail Zygar - Russian Journalist and Author

Stephen Sackur speaks to Russian journalist Mikhail Zygar who has written a book about the powerful groups of people around Vladimir Putin and their influence on decision-making in Russia.

Putin has been criticised in the west as a ruthless and authoritarian ruler determined to revive imperialist ambitions. But is it a mistake to invest him with such transformative power and strategic vision? How tight is Putin's grip on power and what does it mean for Russia's future?