Boris Johnson, the frontrunner to succeed British Prime Minister Theresa May, said on Wednesday that he backs Hong Kong protesters "every inch of the way" in their opposition to a bill allowing extradition to China.
The ex-London mayor, vying with Foreign Secretary Jeremy Hunt to be Britain's next leader, said the people of Hong Kong were "perfectly within their rights to be very sceptical, very anxious" about the controversial plans.
"That could be politically motivated, that could be arbitrary and could infringe their human rights," he said of the extradition bill proposed by Hong Kong's leaders but suspended following huge demonstrations.
"I do support them and I will happily speak up for them and back them every inch of the way," Johnson added while campaigning in the Conservative Party leadership contest to be decided later this month.
Johnson's comments came as May reiterated it was "vital" Beijing respects Hong Kong's autonomy under the terms of the 1997 handover deal from British to Chinese rule.
The outgoing premier said she had relayed her "concerns" to China about preserving Hong Kong's unique status following the recent outbreak of unrest in the SAR.
"I have raised my concerns directly with Chinese leaders," May told British MPs at the weekly questions in parliament session.
"It's vital that Hong Kong's high degree of autonomy and the rights and freedoms set down in the Sino-British joint declaration are respected," she added.
Asked how May had relayed the concerns to the Chinese government, her spokesman said: "It was the meeting with the vice premier, quite recently. I think that's the principal thing that she was referring to."
Vice Premier Hu Chunhua visited Britain in mid-June, when he met May in Downing Street.
The prime minister also said she was "shocked" by the violent scenes at Hong Kong's legislative council building Monday, but noted hundreds of thousands of people had protested "peacefully and lawfully".
China has appeared irked by Britain's public rebukes over the unprecedented anti-Beijing protests that have rocked Hong Kong in recent weeks.
On Wednesday, a Chinese foreign ministry spokesman said Beijing had lodged an official protest with London after Hunt warned of "serious consequences" if it breached the Sino-British declaration.
He added Hunt was "fantasising in the faded glory of British colonialism".
It is the second day in a row that China has slammed the foreign secretary for remarks he has made regarding Hong Kong.
Under the 1997 handover deal from British to Chinese rule, whose terms last for 50 years, Hong Kong enjoys rights and liberties unseen on the mainland.
But protesters accuse Beijing of reneging on that agreement with the help of unelected leaders. (AFP)