Britain summoned China's ambassador on Tuesday to raise the treatment of a British journalist who, according to his employer the BBC, was assaulted by Chinese police while covering a protest in Shanghai.
The incident has stoked long-running diplomatic tension between Britain and China over a range of issues including human rights, China's approach to Taiwan, security laws in Hong Kong and Chinese economic policies.
On Sunday, the BBC said its journalist Ed Lawrence was beaten, arrested and handcuffed while covering protests against strict COVID-19 measures. China's foreign ministry has disputed the account.
Speaking on his arrival at a NATO foreign ministers' meeting in Bucharest, Britain's foreign minister James Cleverly said he had summoned the Chinese envoy over the incident.
"It is incredibly important that we protect media freedom. It is something very much at the heart of the UK's belief system, and it is incredibly important that journalists can go about their business unmolested and without fear of attack," he said.
In response, ambassador Zheng Zeguang issued a statement on the Chinese embassy website, saying that normal law-enforcement procedures had been followed and reiterating the position that reports saying Lawrence was arrested and beaten were false.
"Such a groundless accusation is a distortion of the truth and malicious slander and is totally unacceptable to the Chinese side," he said, suggesting the UK should better educate reporters sent to China by media organisations.
"The UK side must respect facts, be prudent in what it says or does and stop its practice of double standards."
On Monday, Prime Minister Rishi Sunak criticised the Chinese approach to the protests, saying that instead of listening to its people, the government was choosing to crack down further.
That also drew a rebuke from the Chinese embassy, which earlier on Tuesday published a statement saying Britain was "in no position to pass judgment on China's COVID policy or other internal affairs."
The statement added there were "serious problems" with Britain's own COVID policies.
The last time Britain summoned a senior Chinese diplomat to complain was in October, over the treatment of a man who was protesting outside the Chinese consulate in Manchester, northern England.
The man said he was dragged inside the grounds by masked men, kicked and punched, in an incident that was captured on camera. China said protesters had stormed its grounds.
Prior to that, in August, Britain summoned the Chinese ambassador to ask him to explain his country's actions towards Taiwan. China responded by criticising then-prime minister Liz Truss for "irresponsible rhetoric".
A British parliamentary committee said on Tuesday it was visiting Taiwan this week to meet President Tsai Ing-Wen and other senior officials.
(Reporting by William James and Farouq Suleiman; Additional reporting by John Irish in Bucharest; Editing by Elizabeth Piper, Alison Williams and Bernadette Baum)