Amanda Platell: Has David Blunkett even stopped to consider what kind of father he can be to this small boy?

Whoever would have thought that the great social issues of our time - privacy, divorce, infidelity, parental rights - would be brought centre stage by a middle-aged blind man so desperately infatuated with his former lover and deeply in love with a small child that he would risk everything for them?

Whoever would have thought that the great social issues of our time - privacy, divorce, infidelity, parental rights - would be brought centre stage by a middle-aged blind man so desperately infatuated with his former lover and deeply in love with a small child that he would risk everything for them?

And, as more revelations of David Blunkett's relationship with Kimberly Quinn surface, it is clear both that he has risked all for love and that he is likely to lose all.

Even before news that he spent five nights at the hospital bed of his pregnant, married lover and that her son carries his family name, it was clear that Blunkett's brilliant political career was all but over. How can there be a place for a cabinet minister whose personal life is eclipsing the entire government agenda, especially in the precious few months left before an election?

It is intolerable that, as the Chancellor Gordon Brown delivered his Budget for kids this week, it was wiped off the front pages by a paternity battle involving one of his most senior colleagues. It is no longer a matter of whether the Home Secretary will leave office, but when. If he goes soon, there is still a chance he may resume some form of office after the next election.

But even then, would we want a man like Blunkett back in government? When news of the affair first broke in August, I wrote in this newspaper of a moral correctness now blighting our society that meant we felt unable to pass judgement even on our Home Secretary's long-term affair with a married woman.

And if we felt unable to comment on Blunkett's affair then, how do we feel now when we see a man hellbent on exercising his rights as a father clearly at the expense of the child he loves, a child who calls another man Daddy. Blunkett says all he wants is access, but has he even stopped to ask what kind of father he can be to him? Being a father is not just a biological fact, it requires the kind of commitment I doubt a workaholic politician could ever offer.

I have always believed David Blunkett to be basically a decent man, bewitched by a woman who promised him the earth and, in the end, left him in a living hell. Who would not be beside themselves after a passionate three-year affair, having fathered one, perhaps even two children with the woman he loved and thought he would spend the rest of his life with, then to be dumped and have every sordid step of that betrayal revealed to selected national newspapers by "friends" of Mrs Quinn?

But the real question mark over Blunkett's integrity is because of his relentless quest to prove that he is the boy's father. One assumes he will do the same when Mrs Quinn's second child is born next year.

What chance will the Quinn family have of surviving with the constant public humiliation? Stephen Quinn has behaved heroically, this week saying "one should be capable of forgiveness in a marriage." And he's right. But what chance does he have of doing what all of us must do in that situation, of trying to forget for the sake of his family when Blunkett keeps rubbing his nose in his wife's betrayal?

I have the utmost sympathy for any man seeking access to his child, for the pain he must be suffering. But a truly unselfish man would have put the child's interests first and even Blunkett's friends could not say he has done that.

There are no winners in this sorry tale - not Stephen Quinn, cuckolded and cheated of the fatherhood of his children; not his wife, the stained socialite; not David Blunkett, the obsessive, spurned lover propelled by pain. One can feel only pity for each, but most especially for those two children, born into a lie and their lives now defined by the sheer selfishness of their mother and her lover.

Many wonder, what could have possessed Kimberly Quinn to even embark upon an affair with Blunkett just months into her new marriage, to have unprotected sex with another man while she is undergoing fertility treatment with her husband? But in her early forties, as she was then, full of desperation and hormones, it is understandable, if not forgivable, that she hedged her bets and turned to another man as a daddy back-up.

David Blunkett may be the unlikeliest of sperm banks, but that is exactly what he became for this woman hellbent on having a child.

I am sure Mrs Quinn will look back on that time as a period of pure unmitigated madness. I hope for the sake of their children that their marriage survives, but I doubt it can.

And one can only wonder what the sight of a line of bullish male ministers, including the Prime Minister and the Chancellor, attesting to David Blunkett's fine character will do to the precious and precarious female vote at the next election. The sight of male colleagues closing ranks and pardoning their pal will play badly in middle England, especially among women, where bullying, infidelity and the fathering of children inside someone else's marriage are still frowned upon.

Kimberly Quinn got what she wanted out of the affair: the one thing her wealthy, dignified husband could not give her - children. She may have won, but everyone else touched by her has lost something precious, their privacy and their dignity.