You might recall a column I once wrote about a party at the Wallace Collection. It took place in late 2008, the host was the US investment bank Morgan Stanley, and I compared the assembled financiers — who saw the crisis then raging as just one more opportunity to make money out of volatility in markets that were bound to swing round again — to the circle of dancers in Poussin’s ‘Dance to the Music of Time’, which hangs in the Great Gallery there.