This was, after all, a hedge fund that delivered implausibly consistent, and consistently good, returns. These were verified by a firm of auditors employing all of three people. Mr Madoff dealt through his own in-house broker, raising questions about custody of assets and internal control. Many experts felt the options trading strategy he claimed to pursue could not have generated such returns with so many billions under management. Why were professional as well as private investors taken in?

The economic historian Charles Kindleberger believed that “swindling is demand-determined, following Keynes's law that demand determines its own supply, rather than Say's law that supply creates its own demand. In a boom, fortunes are made, individuals wax greedy, and swindlers come forward to exploit that greed”.

In practice, the requisite bait for the greedy is a good story. These used to be colourful – so much so in the 1820s stock market boom in London that they were parodied in a joke prospectus asking for money “to drain the Red Sea, in search of the gold and jewels left by the Egyptians, in their passage after the Israelites”.