The files feature in a legal challenge by businessman Yang Tengbo, who was banned from the UK on the grounds he was a suspected Chinese spy Britain's Prince Andrew sent Chinese President Xi Jinping a letter on his birthday every year as part of a "communication channel" to support the British royal's platform for entrepreneurs,

Prince Andrew was a "key conduit" to Xi Jinping and wrote birthday letters to Xi Jinping, the Duke of Yorks' ex-adviser has claimed in court. Dominic Hampshire alleged that the Duke of York is a "valuable communication point with China" and even regularly exchanged letters with the Chinese President.

Documents released Friday also included a statement from a former close aide to the prince about the duke’s line of communication to China’s president Xi Jinping.