A former employee of Britain’s Hong Kong consulate said Chinese secret police beat him, deprived him of sleep and chained him as they pressed him for information about activists leading the pro-democracy protests, the BBC and Wall Street Journal reported.
Simon Cheng, a Hong Kong citizen who worked for the British government for almost two years, was detained for 15 days on a trip to mainland China in August.
"I was shackled, blindfolded and hooded," the 29-year-old told the BBC.
He told the Journal that he was questioned repeatedly about the role his interrogators presumed Britain was playing in fomenting the unrest.
In fear, Cheng said he disclosed the passwords for his phone and social-media accounts, named two British consular officials he thought had military and intelligence backgrounds and gave details about some people involved in the protest.
British Foreign Secretary Dominic Raab condemned China’s treatment of Cheng, which he said "amounts to torture". He has summoned the Chinese ambassador to express "outrage" at Cheng's treatment.
"I have made clear we expect the Chinese authorities to investigate and hold those responsible to account," Raab told the Journal.
China’s ambassador to London on Monday accused foreign countries including the United States and Britain of interfering in Chinese internal affairs through their reactions to the violent clashes taking place in Hong Kong.
The Asian financial hub, which was handed over to China by former colonial ruler Britain in 1997 but enjoys a degree of autonomy under a "one country, two systems" formula, has been plunged into chaos for almost six months.
Ambassador Liu Xiaoming said Western countries were meddling in Hong Kong's affairs.