Britain has expelled three Chinese spies working in the UK while posing as journalists over the past year, the Daily Telegraph has reported.

The three were understood to be intelligence officers for Beijing's Ministry of State Security, the paper said Thursday, citing an unnamed senior government source.

"Their true identities were uncovered by MI5 and they have since been forced to return to China," it said, referring to Britain's domestic intelligence agency.

All three had claimed "to work for three different Chinese media agencies," the source said, adding they had all arrived in the country over the past 12 months.

It did not name the Chinese media agencies.

UK-China relations have become increasingly strained as Britain has criticised Beijing over its crackdown in Hong Kong and Xinjiang, and barred Huawei from its domestic 5G networks over security concerns.

On Thursday British regulators revoked the licence of Chinese news network CGTN after finding its state-backed ownership structure broke UK law.

The regulator said CGTN's licence holder, Star China Media Ltd, had failed to show it had editorial oversight over the network and that a proposed transfer to another media group would still keep it tied to the Chinese Communist Party.

The English-language satellite broadcaster has long faced criticism for parroting the Communist Party line in its global broadcasts.

In the United States, it is one of seven Chinese media outlets that have been designated as state-sponsored actors rather than as independent media.