China is plugging the last holes in its “Great Firewall” internet censorship apparatus, hampering global groups’ ability to operate in the country.

Five international companies and organisations told the Financial Times that access to the global internet from their Chinese offices has been disrupted in recent months. Some of the companies blamed Chinese telecoms providers, saying the groups blocked crucial software used to bypass censorship.

China aggressively censors the internet, cutting off locals’ access to Facebook, Google, YouTube and much more, to control what news and facts reach its population. A study by Freedom House, a US state-funded non-profit organisation, in November ranked China last in the world for internet freedoms, for the third year in a row.

Multinationals have historically used software known as virtual private networks (VPNs) to bypass censorship and protect their communications from hacking and government surveillance. But in recent months, the companies said, they have had difficulty using their custom-built VPNs.

At the same time, regulators have been pushing multinationals to buy and use state-approved VPNs. The state-approved versions can cost tens of thousands of dollars a month and expose users’ communications to Beijing’s scrutiny.

“China’s intention is to control the flow of information entirely, making people use only government-approved VPNs by making it difficult, if not impossible, to use alternatives,” said Lester Ross, partner at legal firm WilmerHale in Beijing.

In previous censorship battles such as the one that forced Google out of China, the government gradually ramped up disruptions until their targets could no longer operate. “Sometimes China tries to achieve what it wants without saying so explicitly to sidestep the possibility of adverse reaction,” added Mr Ross.

American companies have come to us from a range of sectors — finance, technology, hospitality — reporting disruptions to VPNs, email and file-sharing

Private VPNs are used by businesses to access uncensored news and blocked websites such as Google, as well as banned foreign email and file-sharing platforms.

“This is a significant ramp-up from previous measures,” said Carly Ramsey, associate director of consultancy Control Risks in Shanghai. “The Xi administration has prioritised control over all information flows within China, and in and out of its borders.

“In times of ultimate need, such as a global conflict or a brewing mass movement at home, they want to be able to shut down the data border.”

China has been rolling out regulations to protect its vision of “ cyber sovereignty”, the right of each government to control internet usage and information in its country.

Last January the government asked telecoms providers to “clean up” the internet by closing non-permitted “dedicated lines”, including VPNs, used to “conduct cross-border business activities” by March 31 of this year.

Beijing shut down most domestic commercial VPN services last summer and Apple removed 674 VPN apps from its China App Store last year.

In recent months the government has also disrupted multinationals’ custom-built VPNs.

An American non-profit group and a British company told the Financial Times their company-built VPNs had been blocked, disrupting their ability to do business.

An employee of another American Fortune 500 company said that in recent months it had become increasingly difficult to access blocked websites from their Beijing office, which uses a company-built VPN.

The chief executive of a US tech company founded by Chinese Americans said disruptions from Beijing had forced the group to abandon its use of VPNs. Employees now access the global web using roaming mobile SIM cards, which is expensive.

The groups declined to be named for this article, out of concern that clients would know their operations had been disrupted.

“American companies have come to us from a range of sectors — finance, technology, hospitality — reporting disruptions to VPNs, email and file-sharing,” said Jake Parker, vice-president of China operations at the US-China Business Council, a trade body.

In December, the EU sent a letter of complaint to the Chinese government after two European embassies found their VPN access cut off. The Vienna convention ensures the sanctity of communications between embassies and their home countries.

“This is not just about tightening access, but also giving the government more visibility and control over cross-border connections. The government now has many new tools to make cyber space ‘secure and controllable’ on their terms,” said Samm Sacks, senior fellow at the Center for Strategic and International Studies, a think-tank.

“In a society where the government wants to control the flow of communications and information, secure communications and encryption are certainly an ‘enemy’,” said Sunday Yokubaitis, chief executive of VPN provider Golden Frog.

The Ministry of Industry and Information Technology did not respond to a request for comment.

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