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Simon Cheng Man-Kit did not return to work on August 9 after visiting the neighbouring mainland city of Shenzhen the previous day, Hong Kong news website HK01 reported, citing an interview with his girlfriend and family. Hong Kong has been gripped by anti-government protests in recent weeks, with Beijing accusing Britain and other Western countries of meddling in its affairs.

Britain, the United States and other countries have urged China to respect the “one country, two systems” formula under which Hong Kong returned to China in 1997. Simon Cheng Man-Kit has not been seen for 10 days after he failed to return to work after a business trip to Shenzhen in China on 8 August. Mr Man-Kit, 28, works as a trade and investment officer in the UK's consulate in Hong Kong, based in the Scottish Development International section. Unconfirmed reports suggest he was detained in China while returning to Hong Kong - the scene of mass anti-government protests for months.

A British consulate member of staff has reportedly been detained in China

Simon Cheng Man-Kit told his girlfriend to "pray for him"

We are extremely concerned by reports that a member of our team has been detained returning to Hong Kong from Shenzhen Foreign Office representative

"We are extremely concerned by reports that a member of our team has been detained returning to Hong Kong from Shenzhen," a representative of Britain's Foreign and Commonwealth Office said in a statement released by the British embassy in Beijing. "We are providing support to his family and seeking further information from authorities in Guangdong Province and Hong Kong," the representative said. Hong Kong's Immigration Department confirmed via email it had received a "request for assistance from subject's family member" and "had provided the family with proper advice and practical assistance". JUST IN: Farage mocks Boris Johnson backstop letter to EU – ‘worst deal in history’

Mr Man-Kit has been detained returning from Shenzen to Hong Kong

Simon Cheng Man-Kit works as a trade and investment officer

Protests in Hong Kong have been ongoing in recent months

The Hong Kong Free Press said Mr Cheng's girlfriend had told news outlet HK01 he had planned to return to Hong Kong on the same day he left. Mr Cheng is a Hong Kong permanent resident who had studied in Taiwan and the UK and it is not clear whether he held a diplomatic passport or what documents he used to enter China, the HKFP reported. Asked about the case earlier,, China's foreign ministry spokesman, Geng Shuang, said: "I'm not aware of that."

A Sky News tweet about Mr Man-Kit's detention

Superintendent Kong Wing-Cheung, of Hong Kong Police, confirmed a missing person report had been filed on August 9 but did not offer any more details, stressing no more details had been received from police in mainland China. A spokesman for the SDI said: "We are aware of the situation and Mr Cheng's welfare is our priority. We are seeking further information, working alongside our partners in the FCO who are in contact with Mr Cheng's family, as well as the Guangzhou and Hong Kong authorities." Reports of Mr Man-Kit's disappearance coincide with the revelation that Facebook and Twitter have removed a wide-ranging network of social media accounts and profiles which are believed to be part of a Chinese state operation aimed at sowing discord in relation to the ongoing Hong Kong protests.

A Twitter spokesman said 900 accounts had been discovered as part of a "significant state-backed information operation". Meanwhile, Three people were wounded, one critically, in a knife attack by an unknown assailant near a "Lennon Wall" of colourful pro-protest messages in the city's Tseung Kwan O district in the New Territories last night, police said. One man was arrested. Further protests are planned in the next few days, including by MTR subway workers on Wednesday, secondary school students on Thursday and accountants on Friday.

China restricts social media - including blocking What's App