A few weeks ago I was taken out for a drink by a Wall Street banker. The date didn't start well. The swanky bar had no record of his booking, and he was barely able to contain his rage. He fumed and fidgeted and jabbed angrily at his BlackBerry trying vainly to raise his PA. Five minutes passed slowly.

A table was found, and over our first glass of champagne he told me how rich he was. He had just bought a big apartment in Mayfair, bringing his total number of properties to four. He had started buying art and had become a regular at Christie's.