Matthew Norman: Sometimes you can't keep the private out of public life

Blunkett has forfeited the right not only to privacy but to any role in public life

When the architects of New Labour social policy first embraced the phrase "public-private partnership", they cannot have conceived that its application would one day come to engulf David Blunkett in a whirlpool that threatens to drown his career.

With the Home Secretary, the hard bit is drawing out the dividing lines between what is private and what is public, and deciding how the two should and should not intersect.

For anyone who has missed the salient facts of Mr Blunkett's public-private saga, they are these. Several years ago this trusty swordsman of truth embarked on a sexual relationship with a woman, Kimberly Fortier, who had married another man some three months earlier. Ms Fortier, or Mrs Quinn as she has lately taken to styling herself, is - just about - the publisher of that infamous top-shelf mag, The Spectator.

It cannot be pleasant, to put it mildly, to find the most intimate details of one's life on the front pages of the newspapers. In the normal run of things, one would privately sympathise with Mrs Quinn and her astoundingly saintly husband, Stephen, wishing them luck in avoiding the landmines that Mr Blunkett seems determined to place in a marital path in no obvious need of further detonations.

One might even spare a kindly thought for Mr Blunkett, who is known to be tearfully heartbroken. The man may be a nasty bruiser, and his erosion of whatever remains of natural justice for the love of the right-wing press may be as nauseating a spectacle as British politics can throw up, yet you have to admire someone who has overturned such odds to reach such a high office.

However, Mr Blunkett himself famously loathes receiving special treatment for a disability he has done so brilliantly to neutralise ... and anyway, these are hardly the normal run of things. Mrs Quinn now accuses her erstwhile beau, among other alleged abuses of position, of fixing a visa application for the Filipina who tends to the two-year-old boy reportedly confirmed by DNA testing to be his son.

Mr Blunkett has transcended the conventional boundaries of the cabinet minister, and strayed into the strange and unlovely land of the daytime talk show guest. "David:" his caption on Trisha might read. "Forced Ex-Lover To Undergo DNA Testing And Rushed Through Visa For Own Child's Nanny."

This is not, of course, about the sex. Copping off with a woman who's barely had time to unpack her honeymoon suitcase does little credit to Mr Blunkett's finishing school, in strict truth, and if he did rush through the visa, it makes Peter Mandelson's involvement in the Hinduja passport application look more trifling than ever. Yet if Mr Blunkett had avoided moralising about family values, he might just be able to argue that little of this belongs in the public domain.

It's the hypocrisy, stupid. Five years ago, as Education Secretary, he announced that the national curriculum would strongly emphasise learning about the importance of marriage and the family. The new guidelines, he added, were part of a concerted attempt to make people accept responsibility for their actions. You might argue that, in seeking to establish paternity, he is living up to this aim, possibly through fear. That same year, Alistair Darling announced harsh penalties ("tough and tender" were Mr Blunkett's words for this approach to welfare reform) for feckless fathers who don't support their children.

"Morality is about the nature of our relationships to each other," he told Radio 4's The World At One at the time, while a Christian family values website approvingly quoted him saying: "Strong families and good parenting can enable young people to flourish."

In the dazzling light of such pieties, and the gloomy shade into which he has now cast them, a less arrogant character would have offered his resignation even before the latest allegations surfaced yesterday; and as moralistic a de facto Roman Catholic as the Prime Minister would have torn his hand off in accepting it.

A few months ago, in launching the latest "five-year plan" to beat crime, Mr Blunkett joined the PM in blaming "the permissive 1960s" for the social ills that beset us today, which brings us to the centrepiece of last week's Queen's Speech: the groovy biometric ID cards so urgently needed in the "war against terror" that they are scheduled to be introduced in nine years' time. One of the more transparent idiocies about the cards is that they cannot hope to catch those we are told are the gravest danger - the "sleepers" who embed themselves in society.

David Blunkett, it seems to me, must be a sleeper himself for the very permissiveness he publicly blames for society's ills. He lectures us about marital fidelity while covertly planning, even now deep into his fifties, to inject fresh meaning into that tired old phrase "Swinging Sixties".

Ultimately, as so often with a political downfall, the decisive issue is one of character. In his private and public lives, and in that increasingly chasmic grey area where the Venn diagram intersects, Mr Blunkett reveals himself as a spoilt, petulant bully and a crashing hypocrite. In doing so, he has forfeited the right not only to privacy, but also to any major role in public life.