A British Consulate official has been detained in mainland China after urging his girlfriend to “pray for me” as he attempted to cross the border into Hong Kong.

Simon Cheng Man-kit, a trade and investment officer at the Hong Kong consulate’s Scottish Development International section, had travelled on August 8 to a business event in Shenzhen and was due to return the same day.

The British Foreign and Commonwealth Office said the official had gone missing while returning from the city of 12.5 million that links Hong Kong to Southeast China.

“We are extremely concerned by reports that a member of our team has been detained while returning to Hong Kong from Shenzhen. We are providing support to their family and seeking further information from authorities in Guangdong Province and Hong Kong,” said an FCO spokesperson on Tuesday.

The British embassy in Beijing confirmed to The Telegraph that the official had been detained in mainland China.

His disappearance 10 days ago comes at a time of heightened tension between China and Western nations, including the UK, for their support of pro-democracy demonstrations which have now entered their eleventh week.

According to Hong Kong media outlet HK01, Mr Cheng had crossed into the city via the heavily trafficked Lo Wu border crossing and planned to return the same day using the Express Rail link.

The site published screenshots that evening from a telephone conversation between Mr Cheng, a Hong Kong permanent resident and his Taiwanese girlfriend, identified only as Ms Lee, in which she asks: “Where are you? Just let me know that you are safe.”

View more!

Mr Cheng responded: “Passing through. Pray for me,” but did not answer two subsequent calls from his girlfriend. He has not been heard from since.

The official, 28, grew up in Hong Kong and studied in Taiwan, Tokyo, Beijing and at the London School of Economics before returning to his home city where he took up a position at the consulate in 2017. It is unclear if he entered China on a diplomatic passport.

According to his girlfriend, the British Consulate-General told Mr Cheng’s family to report the case to the police.

An officer at the mainland Chinese police station in Hong Kong’s West Kowloon Terminus told HK01 that there were no arrests made on August 8 or 9.

Ms Lee said that immigration authorities had told her on August 10 that Mr Cheng was under administrative detention in mainland China, but the reason and location of his detention were unknown. Administrative detention in the mainland can last for up to 15 days

Protesters gather for a rally in Victoria Park in Hong Kong on Sunday credit: AFP

The immigration department told The Telegraph that it had promptly contacted the Hong Kong Economic and Trade Office in Guangdong for clarification after being alerted by Mr Cheng’s family.

The department said it had “provided the family with proper advice and practical assistance” and would “maintain close contact” and follow up with them.

His worried girlfriend, described as a financial entrepreneur, told HK01 he had “just started to give back to the community. He grew up in public housing and he used his abilities to get to where he is today.”

Mr Cheng’s Facebook page displays multiple posts about work events relating to trade and investment and also a trip last year to Glasgow and Edinburgh.

In a statement, Ms Lee urged the Chinese authorities to release her partner as soon as possible and to ensure his safety: “Simon’s disappearance confirms a lot of the fears held by the global investment community about arbitrary detention in mainland China,” she said.

Screenshots of earlier messages between the couple revealed that Mr Cheng planned to delete call records and other apps from his phone before passing into Shenzhen.

Fears are rising that authorities are checking phones of passengers to the mainland for any links to Hong Kong’s ongoing protests.

However, Ms Lee has denied any suggestion of a link to the ongoing anti-government protests in Hong Kong, which she said he did not attend or express a view on.

View more!

Mr Cheng’s sudden disappearance while on official duties comes after two Canadians - Michael Kovrig, a former diplomat, and Michael Spavor, an entrepreneur - were detained in China last year during Beijing’s diplomatic dispute with Ottawa over its arrest of Huawei executive Meng Wanzhou.

It is widely viewed that both men - who have been charged with spying – are being used as political pawns.

It also comes as China steps up its use of exit bans against US citizens amid a bitter trade dispute with Washington.

Meanwhile on Tuesday, Carrie Lam, Hong Kong’s embattled Chief Executive, said she hoped the weekend’s rallies, which passed without any violence, were the start of an effort to restore peace to the financial hub.

Ms Lam pledged to talk to peaceful protesters and also to launch a fact-finding study to tackle complaints against the police.

She revealed that Anthony Neoh, the Independent Police Complaints Council chief, had met with British officials who had “personally handled the Tottenham riots in England in 2011” and that the Hong Kong authorities planned to hire overseas experts to provide assistance.