Thugs bussed to a demonstration to assault anti-China activists in California. Relatives held hostage to force an individual to steal corporate secrets from an employer to hand over to Beijing. Intimidating Chinese nationals by following them in the streets of London to send the message “we are watching you”.

This is the work of China’s United Front Work Department, which Xi Jinping, the Chinese president, himself describes as a “magic weapon”.

The organisation is at the centre of the scandal over Yang Tengbo, a Chinese businessman barred from entering the UK over concerns that he cultivated a relationship with Prince Andrew to allegedly influence elite British circles. Mr Yang has insisted his innocence.

British officials believe Mr Yang was “engaging, or had previously engaged, in covert and deceptive activity on behalf of the United Front Work Department (UFWD), which is an arm of the Chinese Communist Party (CCP) state apparatus”, according to a letter quoted in a Special Immigration Appeals Commission ruling.