Hooray. After weeks of holier than thou grandstanding at the Despatch Box and on air about MPs’ expenses and allowances, David Cameron is exposed as a junketeering freebie merchant accepting a jolly from the apartheid racists in South Africa. Or so said weekend headlines. But do I rejoice at the exposure of Mr Cameron’s youthful folly brought to us in a new biography written by James Hanning and Francis Elliot?

Frankly I don’t give a damn. There is no political statute of limitation for say the Jew-hating racists who control the BNP, but should we really care that 20 years ago Mr Cameron flirted with apartheid or should we list Labour bigwigs who once embraced Trotskyism, Stalinism or even worse, were Liberals in their youth?

I think not. Politicians are entitled to their history, their past life, and to making mistakes. Once they were also entitled to a private life as parents, lovers, drunks, gamblers, QCs, property owners, company directors, writers and broadcasters. Today however, there is a concerted effort to declare that politicians have no private life, no right to construct a home, a family, a way of serving constituents that allows them private space which other citizens whose income and expenses come from the public purse take for granted.

The argument is made, fairly, that MPs are in receipt of taxpayers’ money and therefore must reveal all to the public. We are what we spend, argue the press and public.

The fuss is made about someone watching smutty movies and it is paid for by the taxpayer. But all MPs’ income and expenses (unless like Mr Cameron an MP has great private wealth) is paid for by the public.

So too is the income and allowances of teachers, nurses, police officers, consultants who earn billions from Whitehall, every civil servant, all who work for the BBC, every town hall worker, and employees of the new agencies that deliver public goods but are funded by you and me as taxpayers.

Are we entitled to say that only those wholly in the private sector are entitled to some measure of privacy in this new lustration process that holds that all MPs are cheats, swindlers and must be pilloried?

In Poland, the right-wing Kawczynski brothers insisted that everyone who had worked in pre-1989 Poland reveal all their personal details to show that they had no connection to the old communist regime. The object was not historical but political – to deprive all except their own followers of any status as contemporary politicians. A great Pole, Bronislaw Geremek, refused to fill in his form even though he had suffered at the hands of the ancien regime.

Because the approach in South Africa of treating the former upholders of the apartheid regime as humans who had erred rather than criminals to be pilloried was a better way forward.

For David Cameron and Nick Clegg there is more pleasure and they hope political profit in trumpeting their self-righteousness than working constructively to find a solution.

Gordon Brown is not blameless as he refused to accept any of the pay awards made by the independent salary review bodies that have examined what MPs should be paid. For short-term headlines as the man who kept down the pay of politicians, he stored up deep resentments as MPs turned to the allowance system to be able to live decently in both constituency and London.

There are no winners and if there is a Solomon out there who can produce a fair system that covers 650 widely differing needs then please let him come forward.

But the loser in all this is the idea of parliamentary democracy which consists of men and women with their foibles and failings, past and present. They are selected by local party activists and are not asked if they have the personal means to sustain two homes in their constituency and London. They are now collectively under fire as the public in one of its periodic fits or moral hysteria wants to see MPs put in stocks. Destroy a political class however and you hand power over to those who never have to account for their income, allowances and expenses even if paid by the tax-payer.

There will be many new MPs in the Commons after the next election. They will join a Commons in the sourest atmosphere in parliament’s history. Whoever forms the next government will not want a Commons full of the rancour now being created as the private lives of MPs become a playing field for derision and scorn and hate.