The Chinese government has blocked all of the BBC's web services.
The decision to block the services was taken after the corporation decided to change the BBC website's format, having altered its addresses from beginning "HTTP" to "HTTPS".
Although the change is generally considered to be more secure, it has been routinely blocked by the Chinese government.
James Donohue, principal software engineer in BBC News, recently explained in a blog post why the change had been made.
He wrote: "In a climate of anxiety around fake news, it's vital that users are able to determine that articles have not been tampered with and that their browsing history is private to them.
"HTTPS achieves both of these as it makes it far more difficult for ISPs [internet service providers] to track which articles and videos you're looking at or selectively suppress individual pieces of content.
"We've seen cases outside the UK, with some of our World Service sites where foreign governments have tried to do this."
Meanwhile, a BBC representative said: "We regret this loss of service. We continue to work with local service providers so that specific BBC content can be made directly available to our audience in China.
"The last time BBC services were blocked to this extent in China was in 2014 and we call on all parties to observe the UN Declaration of Human Rights, Article 19."
Under Article 19, the right to receive and impart information is protected.