Cheng Siwei, Economist and former vice chairman, Standing Committee of the National Peoples Congress, China

China has overtaken Japan as the world's second biggest economy and remains on course to surpass the US within a generation. HARDtalk speaks to the distinguished Chinese economist, and former vice chairman of the Standing Committee of the National People's Congress, Cheng Siwei. Stephen Sackur asks him whether China's extraordinary rise is sustainable.