British travellers heading to Hong Kong have been warned that their electronic devices could be checked at the border between the city and mainland China.

The Foreign Office has updated its travel advice for people travelling to Hong Kong, amid continuing protests.

#China There are reports of greater scrutiny by mainland authorities at border crossings between the mainland and Hong Kong. More info

Posted by FCO travel – travel advice from the Foreign Office on Friday, August 23, 2019

The online advice reads: “In light of ongoing protests and demonstrations in Hong Kong, there are reports of greater scrutiny from mainland authorities at border crossings between the mainland and Hong Kong.

“This includes reports that travellers’ electronic devices have been checked at border crossings.

“You should be aware that the thresholds for detention and prosecution in China differ from those in Hong Kong.”

It comes after British consulate worker Simon Cheng Man-kit went missing two weeks ago after going on a business trip to the mainland city of Shenzhen.

China said this week that Mr Cheng had been placed in administrative detention for 15 days for violating public order regulations, but did not elaborate further.

Hong Kong Protests
Students and others gather during a demonstration at Edinburgh Place in Hong Kong (Vincent Yu/AP)

Protests in Hong Kong began 11 weeks ago with calls to scrap a now-suspended extradition bill, but have now widened to include demands for full democracy and an independent inquiry into alleged police brutality at protests.

Travellers flying to Hong Kong have also been told to expect disruption and allow extra time for travel over the weekend.

A statement on the Foreign Office website reads: “A large protest action is also planned for August 24 (Saturday) targeting the transportation system to and from Hong Kong International Airport, and in the Kowloon East Kwun Tong area.

“Passengers are advised to allow extra time to travel to the airport.”

Previous advice for travellers reads: “You should be prepared that the situation around protests and public gatherings could change quickly, with the potential for significant violence, especially during unauthorised protests.”

Mr Cheng has been working for the British Consulate since December 2017 as an international trade and investment officer for the Scottish Government.

He and other local staff at consulates and embassies support diplomats, but do not have diplomatic passports themselves.

The Chinese government’s announcement this week that Mr Cheng has been detained in the city of Shenzhen has stoked tensions in Hong Kong, which has been gripped by months of anti-government protests.