On the second last day of last year, Dr Li Wenliang, an ophthalmologist at Wuhan Central Hospital in China, used a social messaging app to warn a group of his medical school classmates about the coronavirus outbreak (though at that time, it was still a mysterious infection).

The local police responded quickly. They tried to intimidate and muzzle Dr Li. They accused him of scaremongering and made him sign a statement to declare that his action constituted "illegal behaviour".