When Alistair Darling introduced a bank bonus tax in December, he said it was not to raise revenues. Clearly, the UK Chancellor of the Exchequer was being modest. Fast forward four months and the Government is now revealing that bashing the bankers (or at least their bonuses) has been a nice money earner.

Darling told the Treasury Select Committee that the reason he had introduced this measure was "to send a clear signal that we need to change behaviour".