China’s ambassador to the UK has defended his country’s long-standing decision to block some Western media companies, in an interview with Sky News.

Speaking to Sky’s Jeff Randall, Ambassador Liu Xiaoming said the websites of the New York Times, Bloomberg, Facebook and Twitter would remain blocked because “they have to fall in the law of China and they have to serve the interests of the people”.

“Are you really saying that you want propaganda rather than the truth?” Randall asked the ambassador.

“No. That’s not true. We are looking for truth,” the ambassador replied.

“We manage the media according to the law. The important thing is that the media, whether it’s foreign or Chinese, they have to fall in the law of China and they have to serve the interests of the people.

“What we are concerned about is the healthy content, is whether it’s in the interests of improving mutual understanding in China.”

Asked what the media companies could possibly publish that would damage China’s interests, Mr Liu said: “You should ask them.

“We expect them to be a good citizen in China rather than spreading rumours and bias against China, and we don’t see that’s the purpose of increasing mutual understanding between China and the outside world.”

The blocking of the New York Times and Bloomberg websites is believed to stem from investigative journalism done by both organisations which exposed the huge wealth of China’s leaders including the country’s current president and general secretary of its Communist Party, Xi Jinping.

Twitter and Facebook are both unavailable inside China because of their ability, as the ambassador put it, to “spread rumours”.

China has its own very popular version of Twitter called Weibo, but because it is controlled domestically, the authorities are able to censor it and delete posts which they deem damaging to their interests.

They are unable to do the same with Facebook and Twitter.

Many users in China, including most foreigners, manage to get round the so-called “Great Firewall of China” using virtual private networks (VPNs) which trick their computer or smartphone into believing it is operating outside China.

Since Mr Xi took office in March 2013, there has been a marked increase in the number of people detained for speaking out online against corruption or other aspects of displeasure with their local or national government.

Those detained include known “dissidents” of the Chinese Communist Party, but also other regular citizens, lawyers and academics.

Despite this, Mr Liu insisted that China was reforming in several key areas.

“Comprehensive deepening reform … five major areas including economic reform, political reform, education, cultural, environmental …,” he said.

“So I think the country will be completely changed as a result of this reform.”

Mr Liu said he believed the West suffered from a significant lack of knowledge of China, and said it was up to the Western media to “open their eyes” in China.

“Unfortunately, Western countries know not enough of China,” he said.

“There is a big imbalance about how much Chinese people know about the outside world and how much the outside world knows China, especially in the Western world, there’s still some people haunted by this so-called Cold War mentality.

“They see China through the stained glass and they see China through their stereotype mindset of China.

“So I think it’s really up to the media, for Western journalists, they have to open their eyes to see the comprehensive picture of China.”

However, foreign journalists operating in China are routinely blocked from carrying out their work objectively.

In March, Sky News faced detention for four hours after mentioning the pro-democracy protests in Tiananmen Square in 1989.

And in November we were forcibly prevented from meeting the wife of the Nobel Peace prize winner Liu Xiaobo.

He remains in jail, convicted of subversion of the government.

Even seemingly simple reports are off limits: a comprehensive look at China’s remarkably impressive high-speed rail network had to be filmed in the guise of tourists because a year-long attempt to get permission to film on trains and stations was rejected by the government with no reason given.