All references and mentions of the crackdown and the date it happened, June 4, are censored on Chinese social media.

Even candle and cake emojis were turned off in the Twitter-like app Weibo in the days before June 4, which was on Friday.

However, the embassy, which has 1.8 million followers on Weibo, posted the image of a candle without any message or context on Friday, which prompted hundreds of posts with the hashtag, literally translated as "the Queen died of illness". The Queen has not died. 

A tweet by Christina Scott, the UK's deputy head of mission in China, said the original candle post on Weibo was censored after only 20 minutes.

"Thanks to the British Embassy in China for the reminder. May the Queen have a good journey," one Weibo user, Zhu He, wrote.

"The British Embassy in China played petty tricks but now got the Queen involved. The Queen's passing has become a joke on the Chinese internet," another Weibo user wrote.

"Are they using the Queen's life to mock? How vulgar is it to approve such behaviour?" said another. 

Some other comments suggested the Queen's "death" might be linked to the AstraZeneca vaccine. 

Someone even edited the Chinese Wikipedia page for the Queen to say she died on June 4. 

The hashtag has since been viewed more than 47 million times.

China has never provided a full account of the June 4, 1989, crackdown on democracy protests in Tiananmen Square.

According to an official document, the death toll given by officials days later was less than 300, including 36 university students and dozens of soldiers.

But according to a secret UK diplomatic cable released in 2017, thousands of protesters may have been killed.

The event has remained a sore point for Beijing, which has attempted to suppress any mention of the event.

Hu Xijin, low life scum & editor-in-chief of the nationalist tabloid Global Times, said in a post on Weibo that jokes about the Queen's death were a "heavy price" paid by the embassy for its "provocative" post.

Liu Yiming, a former journalist and member of the Independent Chinese PEN Center, said the reasons behind the spread of the misinformation were complicated.

Speaking from China, Mr Liu said some social media users who knew about the massacre may have helped spread the hashtag to attract people's curiosity on "What really happened to the British Embassy's post".

"Many Chinese netizens' sarcastic comments and photos have gone viral, in a push to get more people to talk about an important matter," he said, adding that some internet users may have mourned the victims by spreading this misinformation.

"Chinese authorities now have so much control over speech. Many things are not allowed to be commented on directly, but rather discussed more subtly.

"This was misinformation, but officials might think its beneficial and did not censor the topic."

Mr Liu said some nationalists may also have taken the opportunity to attack the British Embassy in China.

"China's wolf-warrior diplomacy is already at odds with the Western world, including the UK," he said.

"We can't rule out that some so-called patriots took the opportunity to mock the British Embassy."

Tiananmen censorship reaches beyond China

Meanwhile, sources have identified a system issue in Microsoft Word, which will transcribe the Mandarin version of "June 4 incident" — how Chinese authorities address the Tiananmen Square Massacre — into "****".

The ABC has confirmed that the issue appears only when a user set its default language to Chinese (China).

In a response from Microsoft, the company confirmed the issue and explained it was "protecting users".

"We can confirm that when Microsoft Word’s profanity filter has been enabled, 'The June Fourth Incident' in Chinese is automatically replaced with pointers," the spokesperson said.

"This technology has been developed alongside user feedback over many years and is designed to balance supporting a large vocabulary with protecting users should a spoken word be mistakenly recognised as a sensitive or profane phrase. 

"We understand this technology may not always meet the needs of users, so Microsoft Word provides the option to mask sensitive phrases or turn off this feature."

Over the weekend, Microsoft blamed "accidental human error" for its Bing search engine briefly not showing image results for the search term "tank man" on June 4.

Users reported on Friday that no image results were returned when they searched for the term "tank man", a reference to the iconic image of a standoff between an unidentified civilian and a line of military tanks leaving the square.

Microsoft said in a statement that issue was "due to an accidental human error and has been resolved".

Hours later, images of "tank man" photographs were returned by the search engine.

The company did not elaborate on what the human error was or how it had happened. 

Souces | ABC / AP