This question was raised in discussions at the British Politics Group meetings at this year's American Political Science Association conference (held for the first time ever outside the US in Toronto).
It was argued that the contrast between a virtuous people and politicians who were screwing things up was overstated. Account should be taken of rising expectations in a post-materialist society and the growing complexity of agendas.
Why was it not all right for politicians to engage in tax avoidance but not businessmen?
It was pointed out that the solution advanced in the expenses scandal of a block of flats to provide homes in London for politicians would not work for politicians with families.
Perhaps the underlying question here was, who would want to be a politician? A salary of £64,000 a year was well above the median salary, but low compared with may professional and managerial salaries. And those jobs do not come with the denigration associated with being a politician. Sarah Childs pointed out that it was possible that the intrusion into private life which was commonplace could be a particular disincentive for women to enter politics.
Of course, more people are coming forward for election than the posts available. What is always difficult to measure is calibre. But it is noticeable that the Labour front bench has no obvious candidate to replace Gordon Brown after an election defeat. In contrast the Conservative front bench have four or five individuals who could replace David Cameron.