What has happened in the past 18 months should teach us that it has become too easy to make money in the financial sector. There is too much cash available and discipline has become slack.

One can inject into the argument many theories about what went wrong. One could, for instance, point out the lack of either good management or detailed understanding of the businesses people were in. One could cite the fact that mortgage-holders did not understand what they were getting into, or the absence of regulation of developing areas of the sector by either banks or the authorities.