In the 2007-08 crisis, many different kinds of financial institution failed or were saved only by state intervention. Large financial conglomerates – Citigroup and Royal Bank of Scotland. Investment banks – Bear Stearns and Lehman. Smaller retail banks without investment banking arms (but with active treasuries) – Northern Rock and Sachsen Landesbank. Diversified banks, such as Fortis, and specialist lenders, such as Hypo RE. Public agencies, such as Fannie Mae and Freddie Mac. America's largest insurer, AIG. Taxpayers will be footing the bills for a generation.

All these businesses exemplified management hubris and, in almost all, the failure was the result of losses in activities that were peripheral to their core business. Otherwise they had little in common. The variety of institutions is matched by the variety of regulators. The list of public agencies supervising failed businesses is much longer than the list of institutions.

There are people who believe that, in future, better regulation, co-ordinated both domestically and internationally, will prevent such failures. The interests of consumers and the needs of the financial economy will be protected by such co-ordinated intervention, and there will never again be major calls on the public purse. There are also people who believe that pigs might fly. Mervyn King, governor of the Bank of England has made enemies by pointing out that they will not.