A Chinese chatbot from Microsoft has been programmed to get a bit coy when being asked about anything remotely controversial.

Known as Xiaobing to its fans (which means "Small Ice") in China and officially called "Ms Xiaoice" by Microsoft, the chatbot has proved popular with the Chinese equivalent of Kevin, that is to say, loves Windows and desperately needs a girlfriend.

Some daring Chinese dissidents decided to test out the theory by asking Xiaobing about the Tiananmen Square protests of 1989, which saw a student uprising against the ruling Communist Party that ended in a massacre.

The result of attempts to chat via WhatsApp rival WeChat, which is the must-have app in China, was a mixture of avoidance, subtle warning and eventually blacklisting.