Britain said on Wednesday that any intimidation on British soil of foreign nationals by China or other states was unacceptable and that it was investigating the matter, responding to a media report about a so-called secret Chinese police station.
Britain has previously said that reports of undeclared police stations in the country were "extremely concerning," and that the police were looking into the issue.
Earlier this week, U.S. federal agents arrested two New York residents for allegedly operating a Chinese "secret police station" in the Chinatown district of Manhattan. China said it firmly opposed what it called "the US's slanders and smears."
On Wednesday, Britain's policing minister Chris Philp said the government was aware of about 100 such stations around the world.
"This government takes interference with foreign nationals here, transnational intimidation, extremely seriously. It is completely unacceptable and we will do whatever is necessary to stop it from happening," he said.
China's embassy in Britain did not immediately respond to a Reuters' request for a comment.
The Chinese government has previously said there are centres outside China run by local volunteers, not Chinese police officers, that aim to help Chinese citizens renew documents and offer other services.
The Times reported on Tuesday that a Chinese businessman linked to what it called a secret police station in London had organised fundraising dinners for the governing Conservative Party.
The local Conservative Party association concerned said it had reported the matter to the security services last year and the man was no longer a member of their association.
Philp declined to comment on the case, which he said was under police investigation.
On the issue of possible political influence, he said: "All political parties need to be alert to the danger that representatives of hostile states seek to infiltrate or influence our activities"
(Reporting by William James, Muvija M and Andrew MacAskill; editing by Philippa Fletcher)