Britain told China's Charge d'Affaires in London that the right to peaceful protest must be respected, after he was summoned to explain an incident in which a protester was seen being pulled into the grounds of a Chinese consulate and beaten.
British police are investigating the incident, which occurred in Manchester, England during a demonstration against Chinese President Xi Jinping. Officers entered the consulate grounds to rescue a man who they said "was dragged" inside and assaulted by several men.
Britain's foreign office said it was extremely concerned about what it called "apparent scenes of violence".
"Today we have made our view clear to the Chinese authorities: the right to peaceful protest in the UK must be respected," said Zac Goldsmith, Minister of State at the Foreign, Commonwealth and Development Office.
China's ambassador to Britain is currently out of the country, so Charge D'Affaires Yang Xiaoguang was summoned in his place to explain the incident. He met with a foreign office official who told him all diplomats and consular staff must respect British laws and regulations.
Commenting earlier on the incident during a news conference in Beijing, Chinese foreign ministry spokesman Wang Wenbin said: "Disturbing elements illegally entered the Chinese Consulate General in Manchester and endangered the security of Chinese diplomatic premises."
"Diplomatic institutions of any country have the right to take the necessary measures to safeguard the peace and dignity of their premises," he added.
'LIKE GANGSTERS'
The protest, involving 30-40 people including Hongkongers now resident in Britain, took place at the start of a twice-a-decade congress of China's ruling Communist Party in Beijing at which Xi is widely expected to win a third leadership term.
Footage posted by the BBC showed a man in a black cap and ponytail being hauled through a gate into the consular grounds, where he was kicked and punched by five men as he lay on the ground.
British lawmaker Alicia Kearns said China's Manchester consul general, Zheng Xiyuan, "had full sight, and was quite possibly involved, in the assaults." The Chinese spokesman, Wang, declined to confirm or deny whether Zheng Xiyuan was involved in the incident.
The victim spent the night in hospital for treatment and an investigation is ongoing, the British police added in a statement.
The man, whose first name is Bob, is in his 30s and emigrated to Britain from Hong Kong recently, according to a friend close to him.
Interviewed by British broadcaster Sky News, Bob said he feared for his life, and showed cuts to his face and bruises on his body after the assault.
"They are like gangsters, you know, doing things like gangsters. It shouldn't be like that. It's not in China you know. This is the UK," Bob told the news channel.
The incident was triggered when several men came out of the consulate to take down protest banners, including one with the slogan: "Heaven will destroy the Chinese Communist Party", and a caricature of Xi wearing a crown.
(Reporting by James Pomfret in Hong Kong, Martin Quin Pollard in Beijing and William James in London; Editing by Kim Coghill, Lincoln Feast, Simon Cameron-Moore, Peter Graff)