Vladimir Putin rules Russia with ruthless efficiency. Opponents and potential rivals know they are engaged in a dangerous game. For proof they need look no further than the fate of Mikhail Khodorkovsky, once Russia's richest man, an oligarch who crossed the Kremlin, and who has been a prisoner for the past decade. HARDtalk speaks to his son, Pavel Khodorkovsky. His father is due to be freed next year, but can Vladimir Putin afford to let him go?