Workers in eastern China making foil papers for funeral rites demand compensation for lead poisoning. In Guangdong, thousands of migrant workers riot for three days after security guards set upon a pregnant hawker. In the same province, migrant workers clash with police after a labourer seeking unpaid wages is stabbed. These are just three of the tens of thousands of riots, protests and strikes that erupt in China each year.

It is not clear whether the number and intensity of protests is on the rise. It could simply be that news of such incidents is spreading – despite the best efforts of censors – via computers and mobile phones. But the perception that local protests might be gaining a broader national coherence is deeply threatening to China’s Communist party.

That is the conclusion of the government itself. A report by the State Council Development Research Center blamed protests on the marginalisation of about 150m migrant workers, the sweat and brawn behind the past three decades of rapid growth. These migrants were discriminated against, the report said. “If mishandled, this situation will create a major destabilising threat.” The government also took seriously a spate of suicides last year at Foxconn, a Taiwanese-owned electronics maker. It encouraged employers to give assembly workers hefty wage increases.