It may be unfair, but David Blunkett should resign

What politicians get up to in their private lives is bound to affect their public standing

The besetting sin of British politics is not the reluctance of anyone to accept responsibility for mistakes, the miserable failure of Parliament to hold an executive to account or even the ease with which MPs settle for a quiet life and a place in government - although all these are present enough; it is the abiding hypocrisy and sanctimoniousness of its debate.

The besetting sin of British politics is not the reluctance of anyone to accept responsibility for mistakes, the miserable failure of Parliament to hold an executive to account or even the ease with which MPs settle for a quiet life and a place in government - although all these are present enough; it is the abiding hypocrisy and sanctimoniousness of its debate.

Take the Blunkett case. Few seriously believe that the question of fast-tracking a visa or giving first-class rail tickets are what is driving this crisis, important though they may be in technical terms of ministerial rules of conduct. In reality, they're just a handle by which opposition politicians can get at the Home Secretary and the media can have fun rehashing all the intimate details of his affair with Mrs Quinn.

But then it is just as sanctimonious to pretend, as the Prime Minister does, that there is some great and absolute boundary between public and private life which cannot be crossed. This would be to make ministers into company executives who can do what they like as long as they reach their sales targets. It's the view that the Prime Minister sometimes seems to take of his Cabinet, but it's now how politics works.

Ministers are politicians responsive to the public and answerable to Parliament. What they get up to in their private lives is bound to affect their public standing if for no other reason than that the public instinctively believes that ministers are representing the country and should uphold some kind of standards.

No, the reason David Blunkett must go, and the Prime Minister should gently push him in that direction if he seems reluctant, is that his private life has become part of the story and, once that is the case, you can no longer carry out your job properly. It may be unfair. It may require of public figures a higher standard of behaviour, or at least a higher degree of discretion, than us ordinary mortals. But it's how it's always been from the days of Charles Stuart Parnell and Charles Dilke onwards.

David Blunkett, it has to be said, has brought it on himself. To listen to some of his supporters, you'd think that he was being hounded out of office for having an affair with a married woman. But he isn't. The press has known about his affair with Kimberly Quinn for more than a year. How could they not have, considering she worked in the media and he was taking her out to dinner, to his constituency home and on holiday abroad with little discretion about it? Yet for the two years of their affair, barely a word appeared in print other than the odd sly remark in gossip columns.

What changed the discretion of the press and released the dogs was David Blunkett's decision to pursue the question of his paternity through DNA tests and talk about it openly to friends and even journalists. Why he should do this, whether it was deliberately to break up Mrs Quinn's marriage and force her to his side or whether it was out of determination to claim his children, is uncertain. But its effect was to propel the relationship into the full glare of publicity and to set off a confrontation with the Quinns, who had decided to stick it out together, that was bound to escalate - and, indeed, has.

Of course, Mr Blunkett will probably get away with it. Just as with the Hutton and Butler inquiries, the man has been chosen and the remit drawn up to stack the cards in Blunkett's favour. He may also find the public more forgiving than the more accusatory in the press. When it comes to sexual affairs, the public is often more level-headed than the media in full moral cry. Disraeli famously retorted when told that the Prime Minister Lord Palmerston was being cited in a divorce case at the age of 79: "He must be planning an election and made that up to attract more votes".

There's no reason to think it would be different today, as Bill Clinton's continued popularity after the Monica Lewinsky affair suggests. In Blunkett's case, it really depends on whether the public see him as a victim of Mrs Quinn's wiles or whether they see the Quinns as a couple victimised by an obsessed lover.

For Mr Blunkett, however, it is hard to see him ever recovering from this. Every time he stands up to bang on about zero tolerance, wayward youths or illegal immigrants, up will come the whole story again. If nothing else, his pursuit of paternity will keep the affair, and the bitter antagonisms it has aroused, alive in public. A sensible prime minister would call him in now, as Edward Heath, Harold Macmillan and so many prime ministers have done with ministers before , and said: "David, I'm sorry, I have every sympathy for your feelings for this woman and your desire to proclaim your responsibility for her children. But it makes it impossible for you to go on as a leading member of the Government. It's better you go now and pursue the matter from the back benches."

Except, of course, we're now in the macho game of refusing scalps to the press, defending the right to privacy, standing up for a decent man and all the other sanctimonious guff that politicians give for avoiding the simple truth that, if you take on public responsibility, you have to behave responsibly. There's always an alternative if you don't like it. You can give up the job.

a.hamilton@independent.co.uk