London summoned Beijing's ambassador for a dressing down Wednesday in a rapidly escalating diplomatic feud over protests in Hong Kong as China told Britain to keep its "hands off" the city and "show respect".
The demonstrations sweeping the former British colony have also revived tensions inherent in the two sides' historic agreement on the global financial hub's handover to Chinese rule 22 years ago.
Hong Kong enjoys broad freedoms and rights not seen in mainland China under a doctrine known as "one country, two systems".
But fears and frustrations over Beijing's gradual tightening of those liberties has spilled over into mass demonstrations against a now-stalled draft law on extradition from Hong Kong to China.
On Monday, groups of mostly young, hardline protesters stormed and ransacked Hong Kong's legislature, daubing it with graffiti such as "HK is not China".
British Foreign Secretary Jeremy Hunt - one of two candidates to become Britain's next prime minister - on Wednesday took the global lead in condemning China's handling of its "special administrative region".
Hunt called on Beijing not to use the protests as a "pretext for repressions" and warned of "serious consequences" if China breaches the commitments it made to London decades ago under the terms of the handover.
His comments provoked a cascade of condemnations from China that began with its foreign ministry in Beijing and continued with its embassy in London.
"He seems to be fantasising in the faded glory of British colonialism and in the bad habit of gesticulating while looking down on other countries' affairs," Chinese foreign ministry spokesman Geng Shuang told a regular briefing in Beijing.
"I need to re-emphasise that Hong Kong has now returned to its motherland."