Over the next six days he will rarely be away from his boss's side. Over 6ft, powerfully built, straight-backed, constantly looking around, the 40-year-old Campbell could pass for a Special Branch man as he guides Mr Blair from reception to reception, interview to interview, through packed bars and hotel foyers. Campbell's brand of protection, though, is different from that of others who accompany the Prime Minister. His job is to head off the gaffe, the verbal slip, the camera designed to grab Mr Blair in awkward pose.
He is also under orders to attack, to stifle bad news at birth, to spin, spin, spin. A journalist who writes knocking copy will be sought out by Campbell and, to judge by past form, dressed down in the conference media centre in the hearing of others. Terms such as "bollocks", "crap" and "tomorrow's fish-and-chip paper" will be used, and loudly.
Campbell, though, is more than just a spin doctor delivering a message. He is a strategist who helps create the message as well. When he accepted the job in 1994, he told Mr Blair to ignore the broadsheets and concentrate on winning over the Sun. That, and the presentation of the abolition of Clause IV, were masterstrokes.
More populist, and popular, than his close colleague Peter Mandelson - he is quick to point out that Mandelson is a politician and he is not - Campbell likes to describe his own role as that of a "permanent support".
Last week he was at home in north London writing Mr Blair's speech. Others, including Mr Mandelson, will have their say, but more likely than not the key phrases that convey the mood, and form the soundbites, will be Campbell's.
As Mr Blair speaks, Campbell will stand to the side, close to the journalists listening to the words he has written. Once the speech is over, and the ovation erupts, he will go to work, seeking out one or two experienced commentators for their instant reaction, assessing how the speech is going to play among the wider public, calculating what needs to be done.
While delegates rush excitedly to the bars and yet more parties and fringe meetings, away from the public gaze a ritual will begin. Political correspondents will flock around Campbell. They will all call him "Alastair" as if he was their friend. In truth, only a handful are genuine friends. The rest would like him to fail, to say something he should not, to go too far. The feeling is mutual. The blimpish man from the Tory broadsheet may be matey, and the self-important junior BBC political correspondent may appear generous, but Campbell knows what they are after. They want a story, an angle, and all he will give them is his story, his angle.
Campbell knows the score. His great strength is that he was once one of them, a tabloid hack who knows how editors think, and he has an instinctive feel for an ambush, a fire-fight ahead. And a war is what he is involved in. This is the age of instant communication and the media are more competitive than ever before. That same chatty bloke could have a tape recorder running. All he wants is for Campbell to drop his guard and he has the front page. It is a battle, and the Prime Minister's Press Secretary and his team are shock troops.
Journalists complain that Campbell does not "do lunch", that they do not see him away from the confines of Downing Street briefings or the Parliamentary Press Gallery any more. His answer to that is typically robust and to the point. Why should he? Journalists get more out of it than he would. When he stopped being a journalist, he cut out lunch meetings. If people have a story to check, they know where to find him: his number is in the phone book.
Similarly, journalists moan that he is a bully, threatening and aggressive. But what do they expect? Yes, they want good news. But bad news, of cabinet bust-ups and government cock-ups, sells better. He knows that. He knows the spin they are seeking. He knows that if a journalist asks him how much his partner, Fiona Millar, is earning as a part-time media minder for Cherie Blair, it is not out of concern for the financial well- being of his household. He also knows that her pay - pounds 12,500 a year - is probably about the same as a tabloid editor's expenses over three months. That makes him angry.
His anger bears only so much analysis. He thinks nothing of dishing the dirt on Tories, of playing the game he professes to deplore. He is a self-confessed propagandist, and will even, if the occasion demands, brief against a colleague. When Clare Short stepped out of line, voicing disquiet over Labour's tax plans, Campbell ensured the story was "turned". A story about Labour's tax plans became a story about the lack of influence of Short. She did not like it, but Campbell, only marginally repentant, took the view that she should have kept her mouth shut.
Unlike the civil servants who served as press officers under John Major - and were often genuinely appalled at the behaviour of the press - Campbell has been there. He was a good journalist. From the moment he joined the Mirror Group training scheme, after reading French at Cambridge and teaching in Europe for a year, he stood out. Campbell's reputation preceded him when, in 1983, he arrived at the Daily Mirror in London. There was something larger than life about this son of a vet, a Midlands lad who had been to a posh university but wrote soft-porn articles for Forum under the pen-name Riviera Gigolo and grabbed the lapels of a senior Mirror journalist he thought was not listening to him.
He was in good company. Ms Millar, his partner, was also a trainee, as was John Merritt, his closest journalist friend, whose early death, from leukaemia in 1992, grieves him still. Campbell's choice of the Daily Mirror had more to do with the paper's pre-eminence as the home of campaigning journalists such as John Pilger and Paul Foot and the writer Keith Waterhouse than a love for Labour. That came later, from the active leftist family of Ms Millar and a rapport with Neil Kinnock.
Campbell's time at the Mirror coincided with Fleet Street's last hurrah. Every newspaper had its characters and its local pub - the Mirror, with Campbell, in the White Hart, or as it was known to its regulars, the "Stab in the Back". Campbell has a romantic attachment to this period, possibly because it allows him to put a distance between the industry he once worked in and the one that exists now. He professes admiration for the news-breaking reporters and campaigners of the time, and bemoans the lack of real independent-minded, story-getters today.
While it is true, however, that "Fleet Street" is not what it was, Campbell's criticism seems out of place. Before he became Mr Blair's Press Secretary he had made his name as a newspaper columnist and TV pontificator, speaking on matters political, usually from a Labour viewpoint - the very sort of journalist of which he now claims there are too many.
He brought to journalism the same fanatical streak he now exhibits at Downing Street. In 1986, his obsessive nature almost did him great harm when he suffered a nervous breakdown. Subsequently, he has blamed his cracking-up on alcohol, and he has not touched a drop since.
It is true that he drank, but not incredibly heavily, and it was pints of beer, not spirits. Perhaps more significantly, his collapse occurred when he had been made news editor of a new newspaper, Sunday Today, in 1986, aged 29. At first he was delighted, touring Fleet Street hiring people, a genuine cock of the walk. But then came a huge anti-climax as the paper's launch was delayed. For five months, the energetic Campbell had virtually nothing to do except run dummy pages and create meaningless layouts. Left to his own devices, he invented jobs for himself to do. He began to worry that he had made the wrong move, and the stress eventually became too much.
Years later, at Merritt's memorial service, he confronted the breakdown by recalling what happened when his late friend visited him. Merritt brought along a bag of marbles and said to Campbell: "Here you are, don't lose them again."
The crisis changed his life. The post-collapse Campbell was very different from the earlier version - less brash, more disciplined, more intensely driven. His deepening relationship with Neil Kinnock - the Labour leader had taken to him on their first meeting - helped shape his socialist beliefs and led him into discussions long into the night about party reform.
He had also become friendly with Tony Blair, then on the bottom rungs of the Westminster ladder. Mr Blair is a close friend of Gavin Millar, a lawyer and the politically active brother of Fiona.
Campbell turned his back on general reporting and became a political correspondent at the Sunday Mirror, then political editor at the Daily Mirror. There was little pretence now about his own politics, which had hardened considerably since he first became a journalist. He wrote unashamedly pro-Labour, Tory-bashing pieces.
If Neil Kinnock had won the 1992 general election, Campbell would have been his Press Secretary. As it was, when he was finally offered the job in 1994 by Mr Blair, the former leader was one of those who urged him not to accept it on the grounds that it would take over his life.
That has duly happened. But protestations that he does not see enough of his young family, cannot get to watch his beloved Burnley play football, and is exhausted after doing the job for three years, fall on deaf ears. He loves what he does, and he is winning.Reuse content