HONG KONG • A former employee of Britain's consulate in Hong Kong has said Chinese secret police tortured and interrogated him about London's role in pro-democracy protests in the semi-autonomous city.

Mr Simon Cheng, a Hong Kong resident, claimed he was shackled to a steel "tiger chair", hung spreadeagled on a "steep X-Cross" and beaten while he was detained for 15 days in August.

British Foreign Secretary Dominic Raab said Mr Cheng's allegations are credible and that the treatment "amounts to torture".

Mr Raab told BBC Radio that he summoned China's Ambassador to Britain Liu Xiaoming to denounce the "disgraceful" and "outrageous behaviour from the authorities in China" which violate international law.

Mr Cheng was placed in administrative detention after visiting the neighbouring southern Chinese city of Shenzhen in August.

He said in a statement on Facebook yesterday that he had taken a high-speed train to Hong Kong West Kowloon station, where he was stopped by mainland police and sent back to Shenzhen.

Mr Cheng said police tied him to a steel "tiger chair", and accused him of being a British spy.

"Sometimes, they ordered me to do the 'stress tests', which include extreme strength exercise such as 'squat' and 'chair pose' for countless hours. They beat me every time I failed to do so using something like sharpened batons."

He was also shackled to an X-shaped frame that kept his hands aloft for "hours after hours", he wrote. "It felt extremely painful."

He said he was asked if he knew anyone who worked for British intelligence agencies, what part he had played in the protests and what he knew about mainland citizens who had joined the demonstrations.

China has repeatedly accused Washington and London of condoning violence in Hong Kong, a former British colony which was handed back to Beijing in 1997.

Chinese Foreign Ministry spokesman Geng Shuang yesterday said that Shenzhen police had "guaranteed" Mr Cheng's "legitimate rights and interests in accordance with the law".

Mr Geng also said he was unaware of any statements from London on Mr Cheng's situation, but that China expressed "strong indignation at the recent series of wrong words and deeds on the Hong Kong issue".

Shenzhen police had said in August that Mr Cheng was detained for violating the Public Security Administration Punishment Law of the People's Republic of China, and the police imposed a 15-day administrative detention on him.

The Global Times, a state-run tabloid, cited police as saying that Mr Cheng had been held for soliciting prostitutes.

Mr Cheng said he felt he had no choice but to make a filmed confession to "soliciting prostitution", a charge that he said was offered by police as an alternative to "indefinite criminal detention".

He also said he has resigned from the British consulate and fled to an unnamed third place and intends to seek asylum.

AGENCE FRANCE-PRESSE