Yesterday in a supposed challenge to George Osborne Shadow Chancellor John McDonnell decided to publish, on his website, his 2015 tax return.
Sadly for Mr McDonnell it's an attempt at a publicity grabbing stunt which lies at the top of a very steep slope.
What is it exactly that John McDonnell is trying to achieve?
Is he suggesting that Mr Osborne is in receipt on income that he is not declaring? One would certainly hope not and if he is he should be explicit about his allegations.
Is he suggesting that he may be in some way better than other MP's because he has no income other than that shown on his partially redacted tax return? Once again if that is the case he should be clear, but he must be careful.
What is better than someone taking no income from other sources? Why, not taking a parliamentary salary either. Is Mr McDonnell implying that we would better served by MP's who do not take an income at all?
Is he suggesting, as Tim Montgomerie rightly observes in today's Times that the potentially higher incomes of partners should also be published? Or that Westminster should be the preserve of the independently wealthy?
Of course John McDonnell, one hopes, is doing none of the above. What he is trying to do is assert what can only be described as the moral superiority of the left.
Back in December 2010 former General Secretary of the Labour Party Peter Watt wrote an article trying to understand the reasons the party had been defeated at the General Election earlier that year.
Mr Watt wrote 'But there is an arrogance at the heart of our politics that is going to make it difficult to really understand why we lost. It is an arrogance that says that we alone own morality and that we alone want the best for people. It says that our instincts and our motives alone are pure. It's an arrogance that belittles others' fears and concerns as "isms" whilst raising ours as righteous. We then mistakenly define ourselves as being distinctive from our opponents because we are morally superior rather than because we have different diagnoses and solutions. It is lazy, wrong and politically dangerous.'
The danger is, and everyone I have spoken with other than hardened supporters of the new regime have made similar comments, that what Mr McDonnell is doing in publishing his tax return is nothing short of the arrogance Mr Watt describes.
The simple fact is voters may not like an 'upper class' attitude of entitlement, although not enough to stop an old Etonian becoming Prime Minister, but they like an attitude of being morally better than you even less.
It is very easy to intimate that in some ways you are better than others but, if I may, I would like to give Mr McDonnell some of the benefit of my own hindsight.
When I was first elected as a councillor it was both the height of the recession and, in the wake of the Westminster expenses scandal, of voters distrust in politicians.
I very vocally said both as a matter of principle and, admittedly, with one eye on the next elections that I would only take my basic allowances and not one penny of perfectly allowable expenses for mileage, parking or subsistence. I would be above reproach, I asked voters to look at the amount I drew and compare it to councillor colleagues. The cost to the taxpayers of me representing them would indeed be exemplary.
And when the next election came last May 7th? I lost.
I lost because of a national swing, many other decent councillors lost that day too, but my record on expenses made not the slightest bit of difference.
When it comes down to it most people don't want their politicians to cheat the system but equally they do not care as long as their elected representatives are working within it.
Who knows, it is entirely possible that I lost votes because of my holier than thou, dare I say it, morally superior attitude?
With the publication of his tax return Mr McDonnell is treading a very fine line. If he publishes his tax return, is it not reasonable to expect MP's of all parties to do the same? Is he sure that all Labour MP's, no, all members of the Shadow Cabinet can assure the public that they too are above reproach?
In seeking to build a distrust of some politicians Mr McDonnell may just have started a process of increasing it for all of them.