Prince Andrew is in trouble again, this time for meeting a businessman who has denied spying for China. In parliament, it has sparked fears about how far the British establishment has been infiltrated by spies. In Beijing, there has been outrage. For Prince Andrew, it has led to him missing Christmas dinner at Sandringham with the rest of the royal family. It is fair to say the accusation that the Chinese businessman Yang Tengbo has been spying for China has caused a serious stir. Dan Sabbagh and David Pegg report