The Foreign Office has said it is "extremely concerned" following reports a British consulate official was detained in China after telling his girlfriend to "pray for me".
Simon Cheng Man-Kit has not been seen for 12 days after he failed to return to work after a business trip to Shenzhen in China on 8 August.
The 28-year-old is a trade and investment officer in the UK’s consulate in Hong Kong. He works in the Scottish Development International section.
Unconfirmed reports suggest he was detained in China while returning to Hong Kong – where there have been mass anti-government protests.
He was on his way back on a high-speed train when he called his girlfriend and told her he was approaching the border when he lost contact, according to HK01. Pray for me, he added.
He has since been reported as a missing person, the news website said.
A spokesperson for the Foreign and Commonwealth Office said: We are extremely concerned by reports that a member of our team has been detained returning to Hong Kong from Shenzhen.
We are providing support to his family and seeking further information from authorities in Guangdong Province and Hong Kong.
China’s foreign ministry spokesman Geng Shuang was asked about the case at a daily briefing on Tuesday and replied: I’m not aware of that.
Shenzhen, in southeastern China, links Hong Kong to the Chinese mainland.
Mr Cheng Man-Kit’s disappearance comes amid pro-democracy protests in Hong Kong which started almost three months ago.
Initially, the demonstrations were over a now-suspended bill that would allow criminal suspects in Hong Kong to be extradited to mainland China.
But broader concerns about the erosion of freedoms under the one country, two systems formula – enacted after Britain handed Hong Kong back to China in 1997 – have now come to the fore.
The protesters want democratic reforms and the city’s Beijing-backed leader, Carrie Lam, to resign.
Sky’s Tom Cheshire, in Hong Kong, said: They [FCO] don’t know why Simon Cheng Man-Kit has been detained. This is very worrying and very concerning, especially considering the length of time which is coming up to 12 days now.
In China you can be put into administrative detention, which means you are basically under lock and key, for 15 days without any reason given to anyone.
When we came over yesterday from Shenzhen to Hong Kong there was increased security at the border. One of our crew members was detained for an hour-and-a-half while they sorted out visa issues.
They have tightened it up since these protests started. They have been checking people’s phones to see whether they have pictures of these protests and making people delete them.
The other thing is the UK relationship with China. The UK has been quite vocal in support for the Hong Kong protests. Beijing doesn’t like that.
We have seen China’s ambassador to the UK standing up and telling Britain not to interfere in internal Chinese affairs.
It is very unclear whether this is anything to do with this, whether it is a complication Beijing wants, or it can do without. They do have another three days before they have to give an official explanation.
But there is a lot of friction here in Hong Kong between China and the UK, and this is certainly going to add more friction to it.