Rarely-seen unrest flared across the country in a critical test of President Xi Jinping’s rule and added to fears for the outlook for the second-largest economy.

China’s stock market posted its biggest one-day plunge in a month and by midmorning, the price of Brent crude was down by more than three per cent, to below $81 a barrel.

Mining giants on the FTSE 100 index were among other areas hit.

Russ Mould, from investment firm AJ Bell, said: “China is a rapacious consumer of global commodities, and signs [that] economic activity is being disrupted by the mounting dissent in the country will be seen as negative for demand.”

“Susannah Streeter, senior investment and markets analyst at broker Hargreaves Lansdown, said the unprecedented waves of protest had “caused ripples of unease across financial markets”.

She added: “Already pockets of violence have erupted as police forces push back at protesters, but there are expectations that a much more stringent security clampdown will be ordered.”