A Border Force officer and his "handler" have been jailed over their work for Chinese intelligence in the UK.

Chi Leung "Peter" Wai, 40, was sentenced to 10 years  and Chung Biu "Bill" Yuen, 65, given an eight year term after being found guilty of assisting a foreign intelligence service, an offence under the National Security Act.

Wai, who used his position to access the Home Office computer system to track Hong Kong dissidents in the UK, was also convicted of misconduct in public office.

The judge Mrs Justice Cheema-Grubb told the men that their actions "threaten the sovereignty of the state" during sentencing remarks at the Old Bailey on Thursday.

The dual Chinese-British nationals were found guilty after a trial last month.

They were involved in what detectives described as a "shadow policing operation...  conducted on behalf of the Hong Kong authorities, and by extension, the Chinese state".

Wai was a former UK police officer who began working as a Border Force officer at Heathrow Airport in December 2020.

He used his access to a vast database of information about foreign nationals in the UK to trace Hong Kongers who had fled pro-democracy crackdowns for his Chinese contacts.

He was sentenced to six years for assisting a foreign intelligence service and an additional four years for misconduct in public office.

Yuen, a former Hong Kong police officer who went on to work as the office manager of the Hong Kong Economic and Trade Office in London, became Wai's contact with Chinese authorities.

The case raised serious questions about foreign interference and the ability of hostile states to gather information on individuals living in Britain.

Cdr Helen Flanagan, Head of Counter Terrorism Policing London, said in a statement that the investigation shows this kind of activity in the UK will not be tolerated.

"I want to be really clear that if you are working on behalf of a foreign state, that we in counter-terrorism policing and with our partners will identify who you are and bring the full force of the National Security Act upon you."

Security Minister Angela Eagle said the government "will continue to hold China to account and take action against anything that puts the safety of people in our country at risk", including Hong Kong police's use of arrest warrants and bounties.

A Hong Kong government spokesperson said the "relevant conviction involved unfounded allegations and smearing" and accused the UK side of initiating the case on "groundless accusations", adding it "abused law and manipulated judicial procedures to secure conviction".

The spokesperson said the allegations in the case were unrelated to the Hong Kong government or its Economic and Trade office in London, where Yuen works, and it would continue to refute the accusations.

In the public gallery on Thursday, a number of pro-democracy activists from Hong Kong watched as the sentences were handed down. Among them was one activist who has had a HK$1 million (ยฃ100,000) bounty placed on her by authorities in Hong Kong.

When Wai started working at Heathrow, he sent a message to the former chief superintendent of Hong Kong Police's Criminal Intelligence Bureau Eddie Ma, who still had links to the Chinese state.

"Will not let any cockroaches in," Wai wrote.

During the trial, the jury heard that "special attention" was also paid to British politicians, such as Conservative MP Sir Iain Duncan Smith.

Wai, who holds both British and Hong Kong passports, has had many jobs - including as an officer with the Metropolitan Police from 2015 to 2019.

He was in the Royal Navy for eight years, and worked for a company providing security for events in Chinatown. Wai had also set up his own company, D5 Security.

After leaving the Met, he became a volunteer constable for City of London Police.

Wai also drew a fellow Border Force officer, an ex-Royal Marine called Matthew Trickett, into his surveillance of Hong Kong dissidents, the court heard.

In 2023, Hong Kong's chief executive John Lee Ka-chiu, its most senior politician, put bounties of HK$1m (around ยฃ100,000) on the heads of some pro-democracy campaigners.

In November 2023, Trickett was tasked by Wai to arrange for high-profile Hong Kong activist Nathan Law, who had a HK$1m bounty on his head, to be followed when he was speaking at the Oxford Union student society.

Trickett was found dead in a suspected suicide soon after being charged alongside Wai and Yuen under the National Security Act. His inquest will be held in November.

Flanagan said the investigation involved trawling through more than 20 terabytes of data, including thousands of messages and information in multiple languages.

Head of the counter-terrorism at the Crown Prosecution Service Bethan David said Wai and Yuen's conduct was "deliberate, co-ordinated and carried out with full knowledge of who it would benefit".

David added: "These convictions send a clear message that transnational repression, foreign interference, unauthorised surveillance, and attempts to operate outside the law will not be tolerated on British soil."

The jury could not agree on a charge against both men of foreign interference by forcing entry into the home of an alleged fraud suspect originally from Hong Kong in Pontefract, West Yorkshire.

The woman's victim impact statement described "significant psychological and emotional impact" on herself and her son, with both experiencing anxiety and sleeping problems and isolating themselves to avoid putting others at risk, the judge's sentencing remarks said.

Flanagan said counter-terrorism policing was seeing a significant rise in the volume of work focused on national security and state threats - with an increase that "far exceeded what we had anticipated" after the National Security Act was introduced in 2023.

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