When George Osborne said last week that he aimed to extract the “maximum sustainable tax revenues” from the banks, he echoed the words of his 17th-century French counterpart Jean-Baptiste Colbert who said “the art of taxation consists of so plucking the goose as to obtain the largest amount of feathers with the smallest possible amount of hissing”. So why does the Chancellor of the Exchequer seem so keen to play down the amount of feathers he has already plucked?

As we report this week, there is a £1.2bn discrepancy between the total raised by the bonus tax - introduced last year by the previous government in an attempt to curb the payment of bonuses by the banks (or at least raise a lot more money from them if they carried on as before) - and the net amount that the UK Treasury and the coalition government say the tax raised.