David Cameron, the UK prime minister, told New Yorkers last week that UK petrol prices (diesel $2.30 a litre) would make them (paying about half that) faint. Chinese drivers can feel woozy on their own account: the country’s biggest fuel price rise in nearly three years will leave Shanghai drivers handing over a record $1.30 a litre, up at least 7 per cent overnight. But the rise, and China’s still-tight control of fuel prices, will do little to help the country’s swooning oil companies.

Both Sinopec and PetroChina reported profits dented by crushed refining margins in the first half of last year. Refining accounts for more than a quarter of operations at both companies and crude price gains since are expected to have pushed the units further into the red. This week’s fuel price rise still leaves operating margins about 10 per cent below break-even, Nomura estimates. No wonder both have trailed the Hang Seng since Monday when price rise rumours began circulating.

Still, since crude began rallying in October, PetroChina and Sinopec have gained a quarter and a fifth respectively. Some of these gains have been based on hopes that China would actually ease price controls. This week’s rise suggests official comfort with slowing inflation. That could mean more hikes to come, but nothing has been said about reforming the pricing mechanism.