LONDON (AP) — A former Hong Kong police officer and a U.K. border official acted on behalf of the Chinese government as secret law enforcement or intelligence agents in Britain, a prosecutor said Wednesday.

Bill Yuen, 65, and Peter Wai, 38, both dual Chinese and British nationals, are on trial on charges they violated the National Security Act by assisting a foreign spy service.

“The defendants engaged in shadow policing operations on behalf of the Hong Kong Special Administrative Region, and thereby the People’s Republic of China,” prosecutor Duncan Atkinson said in London’s Central Criminal Court.

The two acted as if they were legitimate law enforcement to conduct surveillance and gather information about individuals Hong Kong deemed as “persons of interest,” such as pro-democracy supporters, Atkinson said.

Yuen was formerly a superintendent in the Hong Kong Police employed by the Hong Kong Economic Trade Office in London.

Wai worked as a U.K. Border Force officer and was a special City of London constable and ran a private security company.

Prosecutors said Yuen’s work went beyond his job description as office manager of the Hong Kong trade office. He allegedly helped gather intelligence for Hong Kong on pro-democracy activists and politicians who had moved to the U.K. in recent years after authorities introduced a wide-ranging national security law in the Asian financial hub.

Yuen allegedly assigned tasks to Wai, who is accused of using police systems to gather information for his private work that was a cover for his spying. Wai was paid from a trade office account, prosecutors said.

Phone messages showed the two conducted surveillance of former Hong Kong lawmaker Nathan Law and that their interest extended beyond Hong Kong activists, who they referred to as “cockroaches.”

Yuen told Wai to pay special attention to members of Parliament or government employees and in 2023 provided the name of prominent politicians, including Conservative lawmaker Iain Duncan Smith, a co-chairman of the Inter-Parliamentary Alliance on China.

Yuen and Wai have pleaded not guilty to violating the National Security Act by assisting a foreign intelligence service between December 2023 and May 2024 and committing foreign interference by trying to force their way into a home. Wai has denied a separate charge of misconduct in public office.

The trial is expected to last nine weeks.