China on Tuesday said claims that a businessman had used his links with Britain's Prince Andrew to spy for Beijing were "preposterous", after the UK government voiced mounting concerns over the allegations.

British authorities allege that businessman Yang Tengbo was working on behalf of the United Front Work Department, an arm of the Chinese Communist Party that is used to promote Beijing's interests overseas.

An alleged Chinese spy who a judge ruled had formed an "unusual degree of trust" with the Duke of York has been named as Yang Tengbo. He was previously known only as H6 due to an anonymity order protecting his identity, but a High Court judge ruled on Monday that he could be named.