IN SO MANY NOVELS, so many lives and so many tragedies there will be a moment – a short passage, perhaps a minute, perhaps a weekend long – around which the whole thing turns. You will find it on page 77 of these diaries.

It is July 1995. Tony Blair is the new Labour leader. His new press secretary, Alastair Campbell and Campbell’s partner, Fiona Millar, have taken their children for a holiday in France. The couple keep arguing. “I had barely spoken on the way down and rowed most of the time when we did.”

Neil and Glenys Kinnock, close friends, turn up – and immediately Alastair senses that Neil is spoiling for a fight. They argue about everything, Neil storming off for a French dictionary to settle a dispute. But Alastair knows that it isn’t French translation that is enraging the former leader, it is – and it deserves a capital letter – Betrayal.

“He came back with his cheek muscles flexing like they do when he’s close to totally losing it . . . he tried to keep his voice under control, but failed every six or seven words; the hand movements were getting wilder; then the heavy sarcasm – ‘Oh Margaret Thatcher, not too bad you know, not such a bad person, quite a radical, and of course you had to admire her determination and her leadership – that’s what the fucking leader says.’ “ ‘Now, now,’ I said . . . “ ‘Don’t “now now” me. I’ll fucking tell him too – radical my arse. That woman fucking killed people.’ ” Minutes later Kinnock is shouting at Campbell that Blair “had chosen to send his own son to the SS Waffen Academy” (he meant the London Oratory School) then launches into an attack on Blair’s taking “thirty pieces of silver” by “greasing up” to Rupert Murdoch. Oaths fly as Glenys tries to calm things, explaining Kinnock’s sense of hurt. Fiona takes Neil’s side, which wounds Campbell. “There was a chance,” Campbell writes, “our friendship [with Neil] would not recover . . .”

Calm is restored. But something has changed – something hanging in the air has been named: Betrayal. At this point the reader can – must – take sides. The next ten years, the next 700 pages, are either about (as Campbell sees it) an heroic struggle to present a new idea of Labour, or about one man’s descent into nihilism among a small and tightly-knit group of squabbling and astonishingly edgy comrades.

Unwittingly perhaps, this is a brilliant, absorbing account: no doubt partial, but one man’s note, recorded as it happened. If he thought this would make us love or admire him more, Campbell is horribly mistaken, but doubts about whether he had much of interest to report, or would tell it like it was, can be forgotten. Vivid, direct, immediate, and honest in its way, the diary draws you into a world for which “evil” is hardly too strong a word.

Readers who had hoped to discover whether what Tony Blair was trying to do was right – or even sustainable – will miss the point. On Planet Campbell the next day’s headlines, and – always and insistently – his master’s love, are the only landscape.

This is a boastful tale whose subtext is moral disintegration: a story of private wobbles, minor disasters and small triumphs, travelling a road towards who knows where (Campbell has long forgotten) but always at his master’s side. If Bill Sikes’s bull terrier had written an autobiography it would read like this: a snarling, compelling, gut-wrenching splicing of loyalty with faithlessness.

The swearing, a relentless stream of oaths, is leitmotiv to this narrative. However exhausted as he wrote up his diary – and whatever else was excised for brevity – there was always time to write “fuck” one more time.

By abbreviating “GB” and “TB” he shortens this diary by many pages. By writing “f”, “f’d” or “fing” he could have shortened it by many more – but that would have taken the heart out his book; a brutal, big-headed, bullying heart, masculine (the hatred of women is shocking), insolent and profane – yet curiously, tearfully queeny.

Campbell’s well never runs dry of self-pity. He “arranges” Estelle Morris’s resignation. She starts crying. He tells her – tells her – he is finding this “unbelievably draining”. After David Kelly’s suicide Blair “called me a couple of times and said we really have to be strong about this. I said I’m fed up being strong I want to get a life back”. He then weeps “because of the pressures I was under . . .” adding “and the sadness I felt for Kelly’s family”.

Campbell decides that the horror is all the media’s fault. His loathing for journalists annoys many of my colleagues, well aware of how he made his own career. But there is nothing surprising here. Men who use prostitutes despise prostitutes and prostitutes despise the men who use them. Who is the whore and who the client is moot. Still, his railing against “a political press that wasn’t really interested in politics and was obsessed with the trivia” will raise a hollow laugh among the whores of Fleet Street.

This is the diary of a dog, a sort of devil-dog. Rich in detail, powerful in mood, honest within its own lights, it is the more intriguing for the dark and often unspoken presence, at its core, of a mystery: the Master, Blair, “his genius total selfishness”, Campbell quotes Peter Mandelson as saying.

These diaries are His Master’s Voice. They will be gasped at, and relied upon, for decades to come. Buy them: they will suck you in.

The Blair Years: The Alastair Campbell Diaries by Alastair Campbell

Hutchinson, £25; 814pp

Buy the book here for the offer price of £22.50

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