Law, 27, fled the SAR following the introduction of the national security law last summer.

"The UK is clearly a platform for Hong Kong independence agitators, and provides so-called shelter for wanted criminals," Foreign Ministry spokesman Zhao Lijian told reporters.

Describing Law as a "criminal suspect," Zhao called the move "gross interference" in Hong Kong's judiciary.

"The UK should immediately correct its mistake, and stop interfering in Hong Kong affairs and China's internal affairs," he added.

Law wrote on Twitter that he had been granted asylum in the UK after several interviews over a period of four months.

"The fact that I am wanted under the national security law shows that I am exposed to severe political persecution and am unlikely to return to Hong Kong without risk," he wrote.

The activist highlighted the plight of other asylum seekers in the UK from Hong Kong who might not have the same weight of evidence behind their claims.

"I hope that my case can help the Home Office understand more about the complicated situation in Hong Kong.

"To free more protesters from Beijing's authoritarian oppression, the Home Office could consider more comprehensive evidence," he added.

In exile, Law has continued to champion the cause of pro-democracy groups in Hong Kong on social media.

Last month, he hit out at mass trials of activists in Hong Kong saying that they showed that "the Chinese Communist party nakedly abuses its powers and uses the courts to demonstrate that power."