The Third Man, By Peter Mandelson

Want an explosive insider view of New Labour? You had best wait for someone else's memoir, then…

One of my bleaker meetings with Peter Mandelson took place on a drizzly evening in Hillsborough Castle in, I guess, January 2000. He had not spoken to me for around nine months since the publication of my book about him and I had come to see him in the hope of persuading him to talk to me about his job as Northern Ireland Secretary. His reception was as chilly as the County Down weather outside. Without offering me one, this normally hospitable man poured himself a whisky. His stated grievance was the publication of letters between him and Tony Blair on the – inevitable – subject of Gordon Brown and an account of Mandelson's relationship with his partner of the late 1980s.

While both the relationship and the correspondence are mentioned in the book, the letters are covered at greater length. Indeed, how could they not be in a book so dominated by the tempestuous and already much- covered dealings between the first, second and, of course, "Third Man"? Whether or not because he felt the hand of history at his shoulder, he eventually agreed to speak and I wrote two paperback chapters necessarily complemented by classified documents secured from elsewhere and other interviews.

Yet, in his own book there are only about 15 pages (out of 556) – and little new – on Northern Ireland, sandwiched in a single chapter entitled "Being Fired", which deals with his two falls from Cabinet office. He acknowledges that Blair wanted to move faster than he did over demilitarisation but not that he had serious rows over Number 10's eagerness for an amnesty for "on the run" paramilitaries. In terms of book sales, of course, let alone serialisation, Northern Ireland may not be box office. And it may be understandable that Mandelson is less preoccupied with his job in Belfast than his fall from it. While Blair was certainly right to part with him over the undeclared home loan from Geoffrey Robinson, his second fall, over the Hindujas' passports, was far less easy to explain. And while the Blair-Mandelson relationship remained very close, it was changed by it, perhaps irrevocably. Is it too fanciful to think that the book's timing is not only financial opportunism but unconscious payback for the Hinduja firing?

The relatively perfunctory treatment of his second Cabinet job is nevertheless illustrative. The book, to be fair, is not policy-free. While he never really explains why a weakened Prime Minister Brown could not be diverted from the economic course he had set, one of the most interesting sections is on the arguments he and Alistair Darling vainly deployed with Brown in the run-up to the 2009 Pre-Budget Report. Indeed, in terms of political and economic judgement, Darling emerges as the real hero of the Brown premiership. But on the most fateful judgements of the Blair era, Mandelson is laconic. On Iraq, Mandelson records himself as expressing legitimate doubts. And true, he was not in the Cabinet at the time; but he was talking regularly to Blair. Mandelson merely confesses that "despite my misgivings I agreed with him in the end". Yet there is no real assessment – in the year of Chilcot – of why so many others also "agreed with him in the end".

There are lesser throwaways, too. Mandelson reveals that Brown and Blair went to see John Smith in late 1991 to "gauge his intentions" on the possibility of replacing Neil Kinnock. The inference is that the pair would have supported Smith if he had done. But he does not actually say so. Then Mandelson describes in passing how in 1995 Blair's chief of staff Jonathan Powell set out priorities, of which the last was "to avoid the mess Clinton got into when he came to power with no clear idea of what he wanted to do". Mandelson writes that "the longer we were in power though the more evident I think it became that we did not altogether succeed in avoiding that trap". This potentially devastating point is left hanging – a reminder of what a fuller, and perhaps less hastily completed, genuinely inside story of the Blair-Brown years might have been.

As a graphic, if egotistical, account of how the frustrated ambitions of the man with whom he had his most complex relationship helped deform a government, Mandelson's book is a sobering lesson for the future. But this is very far from being the last word on New Labour and what went wrong with it.

Donald Macintyre's 'Mandelson: The Biography' is published by HarperCollins