Britain and the US have condemned the Hong Kong authorities for putting a 1 million HK dollars (£100,400) bounty on the heads of five overseas activists for information leading to their arrest.

The individuals include Simon Cheng, a former UK consulate employee who was granted asylum in Britain after he was detained and tortured in China in a high-profile case in 2019.

He and the others accused, Francis Hui, Joey Sui, Johnny Fok and Tony Choi all fled Hong Kong after Beijing imposed a draconian National Security Law that introduced tough penalties for vaguely defined offences, in an effort to crush the city’s pro-democracy movement.

Police Chief Superintendent Steve Li Kwai-wah said the five activists were suspected of incitement to secession, incitement to subversion, and foreign collusion – crimes that can carry sentences of up to life in prison.

“All of them, who have already fled overseas, have continued to commit offences under the national security law that seriously endanger national security,” Mr Li said.

Mr Cheng responded to the accusations on X, formerly known as Twitter.

“Being hunted by China (Hong Kong)’s secret police, under a one-million-[HK] dollar bounty, is a lifelong honour. If the government deems the quest for democracy and freedom a crime, we embrace the charges to reveal the genuine face of social justice, unyielding to authority,” he said.

Ms Siu, now a US citizen, pointed out that she was being pursued for exercising freedoms in her own country. “I will never be silenced, I will never back down,” she said.

Britain called Hong Kong’s move a “threat to our democracy and fundamental human rights”, and David Cameron, the Foreign Secretary, said he had instructed British officials in Hong Kong, Beijing and London to “raise this issue as a matter of urgency”.

Washington said it deplored any attempt to apply the national security law extraterritorially and that “advocates for democracy and freedom will continue to enjoy their constitutionally guaranteed freedoms” in the United States.

Amnesty International said the decision was further confirmation that the Hong Kong authorities’ systematic dismantling of human rights has officially gone global.

“The brazen tactic of placing ‘Wild West’-style bounties on activists’ heads seems to be emerging as a method of choice to silence dissent,” said the charity’s deputy regional director for China, Sarah Brooks.

Amnesty and other rights groups have also condemned the national security trial of Jimmy Lai, the Hong Kong pro-democracy activist and founder of the now defunct Apple Daily newspaper, which starts on Monday.

“This case has been an attack on press freedom and freedom of expression from the very start. The Hong Kong authorities must release Jimmy Lai immediately and unconditionally and expunge his criminal convictions,” said Ms Brooks.