Mikhail Khodorkovsky is back to challenge Putin’s grip on power. Once Russia’s richest man and head of energy giant Yukos, he spent a decade in jail after challenging the Kremlin. His takedown sent a strong signal to Russia’s powerful tycoons not to meddle in politics. For the first time after his release, he talks about his time behind bars and his vision for a new Russia. He relaunched the Open Russia Movement to strengthen democracy in Russia - a move towards presidency?

"Who is left to take on Vladimir Putin?"