Stephen Sackur is in Nice to speak to former Russian oligarch and billionaire businessman Sergei Pugachev. He was once dubbed Putin's banker; a close confidant who helped Putin reach the top. But their relationship soured. Pugachev was accused of massive financial crimes, he renounced his Russian citizenship and now lives with armed guards in the south of France. What does his extraordinary story tell us of Putin's strengths and weaknesses? Show less