So what's different? As the financial crash fades in the memory, the question most frequently asked, and infrequently answered, is how permanent will be its imprint. To my mind, the answer is obvious. Everything has changed; and, of course, nothing has changed.

Start with the first of these two propositions. I was struck by an observation made by Gao Xiqing, the president of the China Investment Corporation. Surveying the nationalisation of large chunks of the US financial sector, Washington's takeover of the automobile industry, and the soaring federal budget deficit, Mr Gao said he detected “socialism with American characteristics”. Plenty of Barack Obama's Republican opponents would concur.

The US has not been alone in its interventionism. The British government, once as ardent a disciple as any of let-it-rip financial capitalism, now controls two of the country's four largest banks. Tearing up decades of monetarist orthodoxy, it has been printing money to keep the financial system afloat. A hands-off approach to business has been abandoned in favour of what Lord Mandelson, the ever-energetic business secretary, calls a new “industrial activism”.