The man's a patriarchal obsessive

That stern face reminds me of an Old Testament prophet or perhaps Tiresias, the blind seer who plays a key role in Sophocles' Oedipus the King. In at least two versions of the legend, Tiresias is blinded by a woman, either the goddess Athena, as punishment for watching her bathing, or Hera, angered by his assertion that women get more pleasure from sex - by a ratio of nine to one, to be exact. I don't know whether David Blunkett has an opinion on this important question - unlike Tiresias, the Home Secretary has not to my knowledge experienced life as both a man and a woman - but he does seem to have intractable problems with the opposite sex.

His former wife Ruth, whom he met at a Methodist discussion group, left him on the night in 1987 when he was elected Labour MP for Sheffield Brightside. Blunkett wrote about the end of the marriage in his autobiography, On A Clear Day, surprising observers who thought of him as a very private man. "I never wanted to get into a slanging match with Ruth, and I never wanted to hurt the boys," he said later, a remark that suggests a worrying inability to foresee consequences, as well as sounding prophetic of his current difficulties with Kimberly Quinn.

Until now, I have avoided writing about these matters, taking the view that bad behaviour in people's private lives is a matter for the principals to sort out among themselves, even if Blunkett's conduct in recent weeks appears selfish and obsessive; the spectacle of a very powerful man pursuing a heavily pregnant woman through the courts is unedifying, to say the least. Forget Batman and Robin - I assume it is only a matter of time before members of Fathers4Justice scale Tower Bridge dressed as the Home Secretary.

Even more alarming - and this is where the boundary between private and public has been fatally breached - is the impression that Blunkett's private obsessions are spilling over into his role as Home Secretary. He is determined to introduce compulsory ID cards, regardless of the fact that none of the arguments in favour has been proved; only last week, the outgoing Commissioner of the Metropolitan Police, Sir John Stevens, disclosed that a major terrorist attack on London has been foiled without our having to carry the cards that have once again proved so useless in Spain.

Just listen to the Home Secretary trying to justify compulsory ID cards last month, in the middle of his court battle to get access to Quinn's two-year-old son, whose father he believes himself to be: "Knowing your true identity and being able to demonstrate it is a positive plus." This is jaw-dropping stuff, a glimpse into Blunkett's internal world that suggests someone in a state of existential anxiety. The question of "true identity" is a matter for philosophers or the psychoanalyst's couch, while the longing to prove it - to be recognised for who he is - is revealing in a man who has been blind (and by all accounts rather lonely) from birth.

Blunkett is often described as a hard man but it seems to me his most striking characteristic is inflexibility - not very surprising in someone who was raised a strict Methodist, was educated in single-sex boarding schools for blind children and had to confront his father's death in a horrific industrial accident. Such a man might easily display an unusual need for control, as evidenced by his relentless pursuit of Quinn, but now he is trying to limit what the rest of us, complete strangers to him, are allowed to say and do.

His ludicrous proposal to outlaw incitement to religious hatred, which the House of Lords rejected three years ago, has been tacked on to another government Bill, where it will provide protection for every weird belief under the sun - Druids, Satanists, Scientologists, Christians, Muslims, Hindus, the whole damned lot. This is Blunkett at his most patriarchal: his gods will not be mocked, on pain of up to seven years in the slammer. Frankly, I've had enough - I don't see why I should have to live in a society shaped by the Home Secretary's private obsessions.