Some of the evidence which informed the Home Office’s decision to ban Mr Yang was included in a court ruling, external upholding the decision published last week.

Authorities relied on data found on Mr Yang’s devices when he was stopped in 2021, including documents which UK authorities said indicated a link with the UFWD and other Beijing-linked groups.

UK authorities argued these showed he was “frequently connected to officials connected with the Chinese state”. They also said he had “sometimes deliberately obscured” his links to the Chinese government, the Chinese Communist Party and the UFWD, and alleged there was a “deceptive element” to his account.

The Home Office also argued that even though Mr Yang said he hadn’t received direct orders to interfere with UK interests, “those in his position could be expected to understand UFWD and CCP objectives” and “proactively engage in them without being tasked”.

They also pointed to Mr Yang’s membership of the London-based 48 Group Club, which promotes trade between the UK and China. Security officials argued Mr Yang’s honorary membership could be leveraged for political interference purposes by Beijing.

In a response to the US-funded Radio Free Asia, the 48 Group Club said Mr Yang was never actively involved the running of the group.

While the tribunal ruled there was not an “abundance” of evidence against Mr Yang in some instances, and said there may be an “innocent explanation” in others, it ultimately decided there was “sufficient” material to justify MI5’s conclusion that he posed a security risk.

Mr Yang said he will appeal the ruling.

Watch: ‘China’s Magic Weapon’, a 2021 documentary on China’s efforts to expand its influence in the West.