However presented, Alastair Campbell's departure marks the end of New Labour

The really important decisions were taken by four men: Blair, Campbell, Mandelson and Brown. Now only two are left

In what may prove his final touch of presentational genius, at least as a servant of Her Majesty's Government, Alastair Campbell's resignation yesterday contrived to be both an event for which the ground had been prepared and one which came, because of its timing, as a total surprise. Whether deliberately or not, it came at a moment of relative calm after Tony Blair's evidence had seemed to mark a climax to the Hutton enquiry when it was guaranteed to secure the maximum coverage, not only today but in tomorrow's Sunday newspapers. And that in turn reinforces the inescapable meaning of his departure: that it marks the end of New Labour, or at least New Labour as we have known it for just a year short of a decade.

It was, after all, almost exactly nine years ago that Campbell, having spent most of August 1994 turning over in his mind, and in lengthy discussion with (among others Tony Blair and Neil Kinnock) whether he should leave journalism to work for the new Labour leader, that he signed up for the job and began to work out his notice as political editor of Today. As one of a no doubt numerous group of fellow journalists he had mentioned the possibility to at the beginning of that summer break, I can remember thinking that it would be an impossible challenge to resist.

This wasn't, I think, because he didn't enjoy his job. I had known, and liked, him as a colleague since 1987 when he was at the Sunday Mirror and he and I used to lunch politicians together. Apart from a somewhat disconcerting habit - he had of course given up alcohol by then - of insisting on a pot of tea to accompany his meal (a rare request at the kind of restaurant then favoured by the grander Tory politicians) he was in many ways a conventional political journalist, as curious about the electoral mystique of Thatcherism as any of us.

By the time he left, moreover, he was incessantly in demand as a left-leaning pundit on television. Kinnock was among those who advised him against leaving his agreeable life, as much as anything for the toll it would take on his family life. But for a journalist of his strongly partisan Labour views, the lure of working for a party leader rightly thought certain to enter Downing Street was simply irresistible.

The question of where the line can be drawn between Campbell's basic instincts as a tabloid journalist and Tony Blair's own obsession with taming the hostile media that had done so much to damage Neil Kinnock will remain a matter of debate. One reading is that Campbell was the architect of this obsession, as well as the man who went on to execute in practice. And it's true that in those long discussions between Campbell and Blair in the summer of 1994 in the hills of the Vaucluse above the rented Campbell holiday home, it was Campbell who insisted - almost as a condition of taking the job - that The Sun should be wooed to the point at which it declared its support for Labour.

But he was almost certainly pushing at an open door. This was the Tony Blair who had not only learned his media skills from Peter Mandelson but who was also more media conscious than any previous Prime Minister-in-waiting, certainly since Harold Wilson. This was the man who set out to charm newspaper proprietors such as Lord Rothermere - whom he told he would be to the failings of the British welfare state as De Gaulle had been to Algeria and didn't need Campbell to tell him to do so.

Indeed the importance that he attached to securing Campbell's services was evidence of his presentational concerns, greatly reinforced by the scarring experience of seeing what had been done to Kinnock. Campbell had, as Kinnock's closest friend in the press and one of the closest in any walk of life, had seen as much of that as anyone. And Blair had only been half joking when he remarked at one point that if had been dependent on The Sun and the Mail for his information he would not have voted Labour in 1992.

The relationship between the two men became a symbiotic one. The taming - though much more temporary than, surprisingly, either of them seemed to realise at the time it would be - was duly achieved. And brilliant as that achievement was, it may have led precisely to the obsession with press coverage which has been laid bare in much of the evidence to the Hutton inquiry. No Labour leader, as Blair correctly perceived, was ever going to win an election without being much better at presentation than any Conservative leader had needed to be. But almost certainly Blair and Campbell were just a little too inclined for their own good to believe that it was "The Sun wot won it" in 1997. Even in the first term it became apparent that New Labour got into its most serious presentational difficulties when it tried too hard at presentation.

But it put Campbell in an absolutely central role in the Blair project. The seamless continuum between presentation and policy gave Campbell - who was brilliant at his job - much greater importance than any previous incumbent in his post. And this is a measure - despite the signs of growing tensions between the two men in recent months - of the loss inflicted on Blair by his departure. It used to be said by New Labour insiders that the decisions in New Labour that really mattered were taken by just four men: Blair, Campbell, Peter Mandelson and Gordon Brown.

Now only Brown and Blair are left in government, and while Campbell and Mandelson could be said - by and large - to have promoted their leader's interests above all others, Brown as an ambitious elected politician would be a much stranger creature than he is if he saw things exactly the same way on all occasions. True, Campbell is unlikely to leave the inner counsels altogether; there is nothing to stop him advising on electoral strategy without a job in Downing Street. Mandelson, after all, remains a close confidant of the PM. But Mandelson remains dependent on Blair -as well as being a true believer - if he is to get another job in public service which he must crave. Campbell, who may consider a wider range of job options in time, is unlikely to be dependent in this way. And of course he has that diary, the curtain over which was so tantalisingly lifted in his evidence to Hutton.

In one sense Campbell's departure may have been inevitable - particularly as he has often contemplated it in calmer times - once the battle with the BBC, however justified, reached the crescendo it did. There were just the faintest hints in Blair's evidence to Hutton that even he may have thought it had gone too far. But that cannot disguise the loss which his departure is to the Prime Minister. It does offer the ghost of a chance that a more conventional - and perhaps more constitutional - approach to the media by government can now begin. David Hill, his successor, could do a lot to make this happen. But Campbell was a long marcher on the New Labour journey. Mr Blair cannot fail to look more exposed now that he has gone.

d.macintyre@independent.co.uk