More documents about the relationship between Prince Andrew and an alleged Chinese agent of influence are being released to BBC News on Friday.

The court papers about Yang Tengbo’s alleged activities in the UK are becoming public after a legal battle including other media outlets for more transparency in the semi-secret case.

Mr Yang has been banned from the UK on national security grounds after the home secretary concluded that he may have been trying to exert influence on the Duke of York.

Mr Yang, who denies wrongdoing, was accused of using his position as an influential businessman in Prince Andrew’s inner circle to clandestinely further the Chinese state’s aims.

In December, the Special Immigration Appeals Commission said Mr Yang had formed an “unusual degree of trust” with the prince and had not disclosed his links to an arm of the Chinese Communist Party which is clandestinely involved in “political interference”.

The term is used for suspected Chinese state agents who are not operating as traditional spies, but are using their position to secretly influence key figures in the British state, such as politicians, academics and business leaders.

The aim is to subtly and slowly bring them around to the Chinese Communist Party’s aims in a long-term operation often referred to as “elite capture”.

Mr Yang, a businessman who had lived in the UK since 2002, became a key figure in Prince Andrew’s money-making Pitch@Palace scheme that linked entrepreneurs and investors, including at major events in China.

He became an increasingly trusted confidante amid the fall-out from the duke’s interview with the BBC’s Newsnight programme in November 2019, which detailed the Duke’s friendship with sex offender Jeffrey Epstein.

The reaction to the interview led to the prince withdrawing from public duties – and the end of the commercially successful Pitch@Palace events in the UK and China.

Documents show that one of the prince’s closest aides, Dominic Hampshire had told told Mr Yang that he had personally managed to salvage the prince’s reputation in China – and he was ultimately invited in late 2020 to act for the royal in a planned $3bn investment fund.

The “Eurasia Fund” scheme, to be headed by Prince Andrew, aimed to raise cash to invest in Chinese state projects in Africa and the Middle East.

The UK’s security agencies appear to have been concerned about the scheme because it might lead to a member of the royal family advancing the Chinese Communist Party’s aim of expanding its economic and diplomatic influence.

Documents disclosed so far show that Mr Hampshire told Mr Yang that the Newsnight interview had been “hugely ill-advised and unsuccessful” but, in its wake, the Chinese entrepreneur sat “at the very top of a tree that many, many people would like to be on”.

He had assisted in getting “relevant people unnoticed” in and out of Windsor for private meetings with the prince – and he was invited to his private 60th birthday dinner at his mansion.

Another document, concerning preparations for a call between the prince and Mr Yang, reads “he is in a desperate situation and will grab onto anything.”

The documents to be disclosed on Friday include Dominic Hampshire’s account to the court of his role in events, his relationship with Mr Yang and what happened when a currently unnamed UK government agency began speaking to the aide.

Other papers are expected to cover details of the mysterious and aborted “Eurasia Fund” and Mr Yang’s work as a China consultant for major British businesses.

Mr Yang is seeking to appeal his exclusion from the UK on national security grounds.