He is condemned as China's worst traitor. What made him do it? In 1938, as China was plunged into war, Wang Jingwei defected to the enemy, Japan. Yet in his early life, he had been one of the great figures of the Chinese revolution, second only to the legendary Sun Yat-sen. Wang's story is one of hope for a different Asia, liberated from imperialism, and the betrayal of those possibilities. Wang's decision to defect came at China's "darkest hour" when victory against a mighty enemy seemed impossible, and previously unthinkable political choices would tear China into many parts. Understanding why he chose to collaborate with Japan, and how he was in turn betrayed, illuminates one of the great tragedies of China's twentieth century.Presenter: Rana MitterProducer: Ben CrightonResearcher: Elizabeth Smith Rosser.