On a cloudy afternoon last week, a man mounted a busy overpass in Beijing’s Haidian university district, carrying a cardboard box and car tyres.

Wearing an orange worksuit and a yellow hard hat, he easily passed off as a construction worker.

But then, he unfurled two massive white banners covered in slogans written in red paint. He set the tyres on fire. As plumes of black smoke swirled around him, he picked up a loudhailer and repeatedly chanted:

“Go on strike at school and work, remove dictator and national traitor Xi Jinping! We want to eat, we want freedom, we want to vote!”