The most illustrious political suicide since Parkinson - but why?

It is still not clear to me what Mandelson has done that renders him unfit to serve in government

PETER MANDELSON'S is the most illustrious political suicide since the resignation of Cecil Parkinson back in the early Thatcher era. And the most significant. The demise of David Mellor in John Major's day was bad news for the Tory back-to-basics campaign, but Mellor himself was merely an effective (if gobby) minister doing a pretty good job over at Heritage. He was not the embodiment of the new Conservative political idea, nor was he the close confidante of the Prime Minister. But Tony without Peter is more like Bill without Hillary. Geoffrey Robinson's departure yesterday will be infinitely easier to cope with.

Yet it is still not clear to me what Mandelson has done that renders him unfit to serve in government. Indeed, had he resigned only a day later he would (among other things) have given me just enough time to advise readers that I thought he shouldn't and wouldn't. That article would have hung round my neck as permanent testimony to my fallibility, and I have only just been spared from writing it.

But my bemusement, to some extent, remains. As a proposition, I believe that the two circumstances under which ministers should disembowel themselves are a) if they do something badly wrong, and b) - unfashionable this one - if they're bad at their jobs. Taking the latter one first, the consensus seems to be that Peter Mandelson was set to be a good (possibly very good) Trade Secretary; business actively approved of him and the trade unions respected him.

This is not a proposition that finds much support among the journalistic profession. We are, as a breed, generally in favour of resignations. Nothing adrenalises a newsroom like a news flash announcing the unexpected departure of someone powerful: profiles are ordered up, cartoons are commissioned, the "events leading up to..." are chronicled with dates and times. And, of course, the heroic role played by "The Daily X" and "The Sunday Y" in uncovering what previously was hidden, is recalled in positively Homeric language.

And one resignation whets the appetite for another. There is, therefore, very good reason why a government should attempt to apply the Aaronovitch rules to calls for ministerial self-slaughter. Why, indeed, Geoffrey Robinson has been allowed to hold on until now, despite the periodic and frequent appearance of stories alleging minor past misdemeanours. Blair has, since becoming Prime Minister, been determined not to give the press what they want, not to drop body parts into the piranha tank.

So why, then, has Mandelson gone now and so suddenly? Jack Cunningham, the Government's sleek enforcer, was yesterday at pains to stress that his ex-colleague had committed no sin, save error. How can the oh-so-tough Blair administration allow one of its two or three most valuable ministers to be pushed out of office merely for exhibiting "poor judgement"?

One explanation may, of course, be that there is - in there somewhere - a dark little secret waiting to come out, whose disclosure is pre-empted by the resignation. But I doubt it. I do not think that Peter Mandelson is in any way corrupt, though I admit that I've known the man for 22 years, and therefore would probably be the last to find out.

This being the case, Mr Mandelson's resignation acquires a slightly noble aspect. He could maybe have toughed it out a bit longer, but his judgement was that such obstinacy would have done his PM and "the project" a vast amount of damage. In front of his eyes must have swum the terrifying image of Mellor Reduced, a private affair that was to become a soup of football shirts, sucked toes and family snapshots, and culminated in the eventual pretext of the undeclared holiday taken at the villa of Ms Mona Bauwens.

We all have a Mona Bauwens somewhere, if we are investigated with sufficient rigour. The political system in the United States, with its unashamed big-business bankrolling of senators and congressmen, still rejected a series of presidential nominees for high office because they had failed properly to declare their nannies' incomes to the tax authorities.

So we're down to the fact that, as Mandelson knew, the house business just looked bad. The scale of the loan was too large for it to be dismissed as a simple - and repayable - act of kindness (though the argument that it would suffice to buy 20 houses in Hartlepool is not convincing. Frankly, most things will). People would be likely to ask what the lender wanted out of such a large advance.

It may have been for this very reason that Peter did not tell Tony about the arrangement. He knew that it was not a corrupt deal, and that he had shown Mr Robinson no favours when counselling the PM about what to do with the Paymaster General. But he also must have realised, if he thought about it for five seconds, that this is not what others would believe. Yesterday's letter of resignation contains this passage: "We came to power promising to uphold the highest possible standards in public life. We have not just to do so but we must be seen to do so." That is not, presumably, a conclusion that Mr Mandelson first reached in the long watches of Tuesday night.

In fact, he now acknowledges not only that he should have told the PM and his own Permanent Secretary of his arrangements, but that the original loan was itself a mistake. This admission, and his prompt resignation, should separate him from the desperate, last-ditch denials of the last Conservative government. Peter Lilley's denunciation of Mandelson's "hanging on to office" was, for those with memories, one of the two comic highlights of the day. (The other was the greeting of the news in Mr Mandelson's constituency with the words, "this is a dark day for Hartlepool".)

That, however, is not the end of the story. There is a very big lesson here for New Labour, and it is one that they should learn from their friends before their enemies teach it to them in a much more unpalatable way. It is one thing to lose the ancient contempt and hatred felt by the left for wealth creators and the rich. It is quite another to adopt an unthinking admiration for the ways of the wealthy. Tax avoidance, though legal, is not admirable. The rich may be genuinely charitable, but they also use their wealth to purchase influence, much as I use working for The Independent as a convenient threat against tardy officials and inefficient companies. The endowed hardly know themselves that this is what they are about.

In other words, you can be wrong without doing wrong. That sense, not fear of the press, should inform the actions of ministers. Like Cecil Parkinson, Peter Mandelson will be back, for he has done the honourable thing. But the health of the Government (a government that this country still wants to see succeed) depends on maintaining a higher degree of humility than some of its members have shown. They surely know this now.