Some chief executives of global financial services firms are known to keep their minds sharp with an early morning regime of yoga and fresh fruit, but this year the banking crisis has forced many of them to request a diet of doughnuts.

The doughnuts in question are not the deep-fried dough that can cause obesity, but the nickname for something just as unpalatable - a "zero" bonus following one of the worst years in the history of the financial services industry.