Citizen Lab said it had investigated filters set up for customers who wanted something engraved on a new iPhone, iPad or other Apple device. And Apple had a broad list of censored words, not just in mainland China but also in Hong Kong and Taiwan.

Apple insists it is doing nothing wrong and its systems "ensure local laws and customs are respected".

Chief privacy officer Jane Horvath wrote in a letter (PDF) provided to CitizenLab that “the process for engraving is led by our values".  Which we guess she means, money as the last thing it wants is its products to be banned in China’s markets.

The engraving service tried not to allow trademarked phrases, alongside those that "are vulgar or culturally insensitive, could be construed as inciting violence, or would be considered illegal according to local laws, rules, and regulations".

So we guess Pooh Bear is banned.

Citizen Lab's new report found more than 1,100 filtered keywords, across six different regions, mainly relating to offensive content, such as racist or sexual words. But it alleges the rules are applied inconsistently and are much wider for China.

"Within mainland China, we found that Apple censors political content, including broad references to Chinese leadership and China's political system, names of dissidents and independent news organisations, and general terms relating to religions, democracy, and human rights", it said.

The report also alleges that censorship "bleeds" into both the Hong Kong and Taiwan markets. It found: 1,045 keywords blocked in mainland China; 542 in Hong Kong; and 397 in Taiwan. In contrast, Japan, Canada and the US had between 170 and 260 filtered words.