Will Alastair Campbell's diary divulge the truth about life at No.10?

Alastair Campbell returned from a holiday in Scotland at Easter last year, telling friends that he had spent the time asking himself when he should publish his diaries: "Am I really going to do nothing until the Tories are back in power?"

It was a deceptively simple question. When he left No 10 four years ago, he assumed that he would not publish until Labour were out of office. But because he remains fiercely, viscerally, tribally Labour, he cannot bear the idea of his side losing. That was why he came back to work on the 2005 election campaign. And that is also why The Blair Years is going on sale next week, just 12 days after Tony Blair stands down. He knows his diaries are a wasting asset, declining in value as the period they describe recedes. But I do not think he driven by money. He wants to publish because he wants to defend Blair's record and thinks the Labour Party should, too. He thinks Gordon Brown and the Labour Government will be stronger if they have more confidence in "the Blair years", and he is arrogant enough to think that his account from the heart of the machine will help to rebalance the negative spin that journalists have put on his time at the centre.

For three years in opposition and for most of the first four in Government, he managed a relationship between Blair and the media that projected one of the most popular and electorally successful politicians this country has ever known. He was the transmission mechanism, in charge of "message discipline" and therefore in charge of both the message and the discipline. That meant friction with politicians, officials and journalists - friction that turned into grinding abrasion as the mood of the country towards Blair changed.

In the early years, the friction was good-natured. Simon Kelner has a framed letter from Campbell in his loo dating from soon after he became editor of The Independent in 1998. It reads: "Dear Simon, Please could you mix some water with the bile that your leader writers seem to have been drinking recently. Yours ever, Alastair." I was one of those leader writers, but the first I heard of the letter was when I spoke to Kelner about this article last week. "That is an example of the combative relationship I, and most editors, have had with Campbell," he said. "It was informed by sharp exchanges of opinion and some wit."

When, on 9 July, journalists seize what some of them are already calling "The Campbell Years", they will be looking for Campbell's role in, and his defence of his role in, a series of media firestorms that raged from one "worst week" for Blair to another. Campbell knows that they will be looking for that, and wants to avoid giving them the chance to re-run a greatest hits of Headline Crises, from Bernie Ecclestone to the Queen Mother.

That's why the book has been heavily edited. Campbell spent the first two years after he left No 10 - "not full time", he reassured friends - simply transcribing the 2.5 million words from his "shorthand hieroglyphics". For the last year, he has cut the vast work down to a mere one-seventh of (omega) its length - in the course of it removing anything that might embarrass Gordon Brown, or the Labour Party, and, as we learned in May, cleaning up the f-words and the c-words uttered by Tony Blair.

And the journalists who will rush to look themselves up in the index - which Campbell admitted on his blog on the publisher's website to double-double-checking - may well be disappointed. According to one source familiar with the text, Campbell "doesn't mention journalists much at all".

I mentioned this to a media executive who will certainly be looking himself up in the index, who muttered: "There's going to be nothing in it about journalists. Nothing about Tony Blair. Nothing about Gordon Brown. Nothing that would embarrass the Government. There's not going to be much in it, is there?"

Well, there is going to be a lot about how the Government tried to turn round the big public services, and how it tried, not always successfully, to get the positive messages across about delivery. But Campbell cannot have written 350,000 words of the vivid and spare prose of which we caught a glimpse in the Hutton inquiry - "GH [Geoff Hoon] and I agreed it would fuck Gilligan if that was his source" - without providing some big stories.

The big deal is, of course, Iraq, and Campbell's role in making the case for war. He was asked in his first big interview after leaving Downing Street whether he thought he had overreacted to Andrew Gilligan's BBC and Mail on Sunday reports that he had "sexed up" the intelligence on the threat from Saddam Hussein. "No. It went beyond the pale. A friend rang me up and said, 'You've got to do something. Just understand what is being said: you lied so mothers' sons could go and get killed. Not you lied and that was the effect, but you lied and that was the purpose. You cannot leave that.' That's how I felt, that's how I still feel."

There can be no doubt that he feels like that now, and wants to make his case again, in the way he feels that the anti-war conspiracy case has been endlessly rehearsed, without much rebuttal - although I understand that some of the material in the diaries about intelligence has been censored by the spies.

That January 2004 interview was interesting for this, too: "I don't mind the knockabout: 'Is he off his trolley? Has he driven out the demons?' But this one got through and I thought: 'I'm not putting up with it.' " He did have demons, as a former alcoholic who has gone public recently in this newspaper about his experience of depression, or bipolar disorder.

And there was some knockabout. He would tease journalists. I remember him coming into The Independent's press-gallery office in the House of Commons - a tiny room that had once housed a photocopier and then housed up to six journalists - and looking over political editor Don Macintyre's shoulder at his screen. "You can't have 'not' in the first par," he said. It was the sort of thing you can do only to someone you like. And he was right.

Another time he stopped by the office, the knockabout (omega) went the other way, when David Aaronovitch, then the parliamentary sketch writer, asked him: "Alastair, what deep inner sadness did your alcoholism conceal?" Campbell made the mildest of faces, and left the room.

First, though, we should try to get Campbell's motive for early publication straight. He is not in it for money. If he had wanted money, he would have sold the rights to serialise the book to a newspaper that would have paid hundreds of thousands of pounds. Publishing-industry insiders were astonished when Random House announced that the book would not be serialised before publication. "I can't remember that happening before," said one.

Indeed, Campbell could have made squillions since leaving Downing Street if he had been prepared to go into what is known as "public affairs consultancy". "He is quite proud of the fact that he has done no lobbying at all," said a friend. "He's advised a few companies and charities, but says he doesn't 'get his rocks off' on that kind of stuff." Somehow, Campbell seems unlikely ever to join the advisory board of PepsiCo, as two of his friends did last month: Alan Milburn, the former Health Secretary, and Philip Gould, Blair's opinion pollster.

Campbell already earns enough to live on comfortably from his after-dinner speaking and occasional journalism. Earlier this month, he reflected to a friend that he had "got quite used to the idea that maybe you don't need to have 'jobs' ".

Meanwhile, his diaries have absorbed a great deal of his extraordinary energy and perfectionism. He knows he is a control freak, and is proud of his attention to detail. Someone who called him just before the book went to the printers caught him in a moment of characteristic ebullience. Proof-reading the text, he had just realised that he had missed an acute mark off a French word. "I'm very, very glad I spotted that," he said.

Despite the crack he once made about his diaries being his "pension", then, what he is really after is self-justification: for himself, for Blair and for the Labour Government. Yet this motive for early publication also lends itself to misinterpretation. His critics often portray him as a bitter man adrift. They enjoy the caricature of him sitting at home, waiting in vain for the special phone to ring, the one with the number known only to the Downing Street switchboard, plotting his return to centre stage, crazily convinced that a grateful nation would finally realise how important - and right - he had been. Certainly, Campbell admits that he found the adjustment process hard - just as Blair said ruefully to Martin Amis that, although in May he felt all right about letting go, he would probably be clinging to the No 10 doorknocker when the day finally came.

But Campbell has "got over it" more than many of his former adversaries in the press, according to one friend, Tom Baldwin, the former Lobby journalist for the Times who is now Washington correspondent. "Some of the Tory journalists never got over him. There was a very boys'-school atmosphere in the Lobby and they all wanted to be liked by Alastair. When they found out that they weren't, they were furious. He got over it before they got over it: they'll take their slightly sexually charged obsession to their graves."

Certainly some journalists became very hostile to him, particularly after the war - of which more in a moment. But often this was balanced by respect. One senior journalist who fell out with the Blair Government, and who believes that Campbell helped to "poison the well of public discourse", nevertheless likes and respects him. "The test is whether, if you are at a party and someone comes into a room, your heart sinks or soars. If Alastair came in, your heart soared," he told me. He remembers occasions when he and Campbell "shouted and screamed" at each other on the phone, "but it was always on the basis that he was doing his job, and I was doing mine".

Given his strong views about the failings of the Daily Mail and the BBC in particular, Campbell has been remarkably restrained in his dealings with the media since he left No 10. He left friends in no doubt that he thought Blair's "feral beast" speech was "a bit soft" - he saw the text in advance but says, on his publishers' blog, that he "did not influence the content". He has avoided becoming a commentator, and refuses to be interviewed about the diaries before publication. He wrote about sport for The Times for a while, which I am told he described as "quite good therapy" because many of the interviews he did with famous sports people centred on the theme, "What on earth do you do with yourself after you've been top in your field?"

He also wrote a few sharp columns about politics - such as one in February saying that David Cameron had made a mistake in calling for Blair to resign. "In opposition, Mr Blair never called for resignations unless he thought that they could happen... [Cameron] made the call not because it was the right thing to do, but because he thought it was what the public wanted to hear. Wrong call. He is right to try to stay in the centre. He is wrong to act as a mere pundit, an upmarket Alex Salmond."

But he has resisted the temptation to get back into full-time politics, "going over the top with bricks and bottles", as Sir Richard Wilson, the Cabinet Secretary, once put it. He seems surprisingly well-adjusted to the quieter life. One friend said: "He told me he knew it was corny and cheesy,(omega) but his oldest son is at university and he loves the fact that he could just bugger off and see him."

He had confided to the same friend that one of the most important features of his time at No 10 was the "constant feeling of guilt" about not seeing more of his children. He took the job as press secretary to the Leader of the Opposition when his daughter, 13 this year, had just been born. His two sons were already teenagers by the time, in the autumn of 2003, he resigned as the Prime Minister's director of communications and strategy. For most of the past four years, though, he has "been there at the beginning of the day and at the end of it, which means a huge amount to him".

Like Blair, "he knows where the washing machine is", said this anonymous friend, but doesn't get involved in that side of things. "He deploys the well-worn male tactic of not being any good at them." He runs, famously, and plays golf, a less well-known pursuit.

Fiona Millar, his partner - they are "far too left-wing to get married", said another friend - has made a similar adjustment to an active but less intense life. For most of Campbell's time in Downing Street, she worked there too, as Cherie's press secretary; now she is chair of the Family and Parenting Institute and a columnist for the Guardian's education section. Last year she campaigned against Blair's trust schools bill, which got through the House of Commons only with Conservative support. Campbell quietly let it be known that he sided with her rather than his former boss. In a rebellion that went to the heart of the Blair circle, Campbell turned up at a protest meeting in Westminster chaired by Lord Kinnock.

His other return to active politics was for the 2005 election campaign, on which he worked, initially part-time, for about nine months. We only know about his role, though, because his £47,000 fee had to be declared to the Electoral Commission under what he complained about to a colleague were "the ludicrous laws that we brought in on party funding". (More attention was paid to Cherie's £7,700 hairdresser's bill, paid by the Labour Party, and the £3,600 paid by the Tories for Michael Howard's make-up.)

Yet his part in the 2005 campaign was not a reversion to his previous role. This time, he was not Blair's man but the Labour man, on a mission to keep Gordon Brown on board in the interests of the party. Indeed, he was instrumental in persuading a reluctant Blair that he had to give Brown a bigger role in the campaign - thus sealing more than two years ago the succession that finally took place last week. Since then, he has continued to be the "stable and orderly transition" in human form. Just before Blair's resignation announcement in May, at a party for outgoing Blairite apparatchiks, Campbell made a speech urging them all to "unite behind Gordon". Sources close to Brown say that he and Campbell are still in touch, although this may refer to "cut out and keep" conversations: about which bits of the diary to cut out and which to keep.

Campbell could never be a total Brownite. None of Blair's close entourage who had daily experience of working with the Chancellor is - although the further and better particulars of why not are among the bits that were cut out of Campbell's record. But he could not be for the very reason that he is publishing his diaries in the first place: because he fears that Brown's people want to trash Blair's record, forgetting that their man was part of it. Campbell presumably agrees with Martha Greene, the Blairs' confidante who is managing the refurbishment of their Connaught Square house, who told guests at a party three weeks ago that Brown should "remember Al Gore". The inner Blair entourage plainly fear that Brown might repeat Gore's mistake of distancing himself too much from Bill Clinton, with whom he had served for eight years as vice president, which ended in his failure to win the US presidency.

Campbell believes - naively perhaps - that a contemporaneous account of what really happened during the Blair years will prompt a more balanced view of the period. Those who have read The Blair Years say it has changed their perspective on things about which they had only read in the newspapers, presenting a picture, according to one, of "people who are only human beings trying to do a difficult job as best they can". Although the select few who have read Campbell's manuscript are hardly "don't knows" on the question of Blair's record. It is just as likely that it will be used as an excuse to rehash all the familiar complaints about "spin" and Campbell's role as its evil high priest.

For a long time, Alastair Campbell was supreme in his ability to "read" the media - what angle journalists would be interested in, or which nugget from a speech or policy document they would seize upon (especially if it were drawn to their attention). We know from the Hutton Inquiry that Jonathan Powell, Blair's chief of staff, asked Campbell by email what he thought the headline in the Evening Standard would be on the day that the Iraq dossier was published. But now, I suspect, even Campbell has no idea which of the stories in The Blair Years will be "the big story"next week. But of one thing we can be sure. He's not in it for the money. s

'The Blair Years' is published on 9 July by Random House, £25

Interesting? Click here to explore further