Leading article: Seeing through transparency

There are some things no politician can be against: equality used to be the most fashionable aspiration, now it's transparency. Indeed, on the basis that no one could argue for its converse, opacity, we are all in favour of transparency now. There was once a time when the emperor's new clothes made him look ridiculous; today it's all the rage for those who govern to parade naked.

The Chancellor, George Osborne, has declared that he would have no problem releasing his own tax returns and would encourage other ministers to follow suit. He wants to be able to prove that he will not personally benefit from lowering the top rate of tax. And he probably does not care to be trumped by his cabinet colleague Vince Cable, who said the same. But there must be shyer Tory colleagues who would feel differently about exposing their means, though sometimes they do so inadvertently, as the Cabinet Secretary, Francis Maude, did in assuming that everyone has a garage. If modest means are attractive to voters, then Tories are bound to lose out.

The new imperative for openness was also bolstered by the spat between the main London mayoral candidates, Ken Livingstone and Boris Johnson. Mr Johnson boasted that his tax affairs are as straightforward as Mr Livingstone's are complex. As Ian Birrell writes today, the exposure of Mr Livingstone's tax arrangements could be fatal to his chances, not because they are illegal, but because they are at odds with his own rhetoric about tax and those who aspire to public office.

The Prime Minister has been obliged to pay homage himself to openness after the embarrassment occasioned by the former co-treasurer of the Tory party seeming to promise would-be donors that sufficiently large gifts to the party could buy not merely access but influence over policy. There is no evidence that trade-offs of this sort have taken place – at least, nothing on the scale of Tony Blair and Bernie Ecclestone – but the damage is done. The Prime Minister must now publish details of his social encounters with donors. If some of these people are his friends, and he is therefore obliged to put his social life on the public record, he has only himself to blame.

Under this prime minister, as happened under Mr Blair, social and political life have overlapped in a way that is not altogether wholesome, though in Mr Cameron's case it is not political donations that are the problem. The revelations about his Chipping Norton encounters with Rebekah Brooks (seemingly, she met Mr Blair in London) and other representatives of the Murdoch press suggest that the personal became very political indeed, even if nothing so concrete as cash changed hands. These encounters are properly in the public domain.

Is it altogether to the good, then, that we should be more and more open about more and more things? Not entirely. Tony Blair has said he regretted his introduction of the Freedom of Information Act because it did not turn out as he expected. Certainly, it has exposed a good deal about the workings of government and the misgovernance of public services, but we would be deluding ourselves if we imagined that government is now fully open to scrutiny. Rather, it is clear that when formal proceedings may be made public, many of the real decisions are taken in corridors or in private homes between the people who matter. If cabinet discussions are not given some protection from publication, it is likely that they will neither be as full nor as honest as they should be.

The trend for politicians to publish details of their personal financial affairs also has its drawbacks. It began in the US where Mitt Romney's wealth is a matter of record. But in the US, they see wealth as a mark of success rather than something slightly shady. And if wealth is to be measured by assets as well as income, not many politicians will be perceived as being one of the people. The greatest exercise in involuntary transparency – the publication of MPs' expenses – triumphantly vindicated the principle of openness, but it brought almost the entire political class into disrepute.

We should, then, on balance, favour transparency – but in a clear-eyed way. Not all the workings of government can be open to scrutiny, not every encounter between a party donor and a politician is a conspiracy against the public, and not every rich individual entering politics is inherently suspect. But if politicians are now engaged in competitive self-exposure, the spectacle may be eye-opening, and certainly should be fun.