Alistair Darling on Wednesday came as close as any chancellor can to admitting that the government’s own forecasts for growth and inflation – made with such optimism on Budget day just three months ago – are wrong.

Before the assembled ranks of City grandees at the annual Mansion House dinner, he went so far as to warn that a period of belt-tightening was now in order. He warned: “Times are tough. It will take time for these global difficulties to work through.”