It is not just investment banks and hedge funds that must reinvent their business model. Private equity has to do things differently in the future, otherwise backers will disappear, the money will dry up and credibility for the profession will be destroyed.

Some of the problems are externally generated; but many are self-inflicted. The difficulties of 3i, its shares at a 75 per cent discount to book and below their issue price, is a demonstration of the underlying crisis.