Britain has never known a more tortured public figure than Gordon Brown. Judging by a snippet from his new book, the torment continues in private.

In My Life, Our Times, Gordon does some anguished reflecting on the Iraq war. Almost a decade and a half after the event, and more than seven after he left Downing Street, it still plagues him. As it should.

Gordon cannot formally accept any guilt for what he did (or failed to do) to enable an indelible national disgrace. Owning any offence graver than not emoting enough for a reality TV electorate is too much for his brittle pride to bear.

But one trait that seems to distinguish him from Tony Blair is a capacity to feel guilt, even if he expresses it obliquely in the language of denial.

As Prime Minister, this was visible from his subtle method of confessing to telling whoppers, which was to mention how his father taught him and his brothers always to tell the truth. Referring to his dad when accused of dishonesty was as blatant a tell as Le Chiffre bleeding from an eye when bluffing 007 in Casino Royale, or Homer Simpson whooping with joy on being dealt four jacks.

With Iraq, the tell takes the form of an intendedly rhetorical question that isn’t rhetorical at all.

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On the surface, where the headlines are generated, Gordon chooses to pass the buck to the Americans for failing to share an intelligence report about Saddam Hussein’s limited military capability. Had he seen it at the time, he claims, he would have known then that the “war could not be justified as a last resort”. The war, he adds, “cannot now be seen as a proportionate response”.

It would be hard to compute that someone of his intellect could be foolish enough to use that “now”, were it not for the fact that when it comes to appraising his own credibility, the man is a dunce.

In 2009, after coming within a whisker of sacking Alistair Darling as Chancellor, he categorically denied having considered it. Of course he wasn’t lying, he said when challenged. Dad taught us to tell the truth.

He doesn’t mention his priestly sire in the Iraqi context, but he might as well. Claiming he needed a US intelligence report to realise the war was unjustified is a sufficiently crude insult to his own and his audience’s intelligence to qualify as a gigantic tell.

Robin Cook had not read that report when he resigned in protest against the war, and nor had the millions who marched against it. Brown asks himself “over and over again whether I could have made more of a difference before that fateful decision was taken”, he writes, but he might as well ask himself over and over again if he has a nose.

It isn’t, pardon me for the pedantic textual analysis, that he could have made more of a difference. So far as British involvement, he could have made all the difference. He could have stopped it.

He could have done so at any time between the summer of 2002, when Blair’s desperation to join Bush in the fiasco became plain, and March of 2003. All he needed to do was threaten to resign if Blair took an unwilling country to war without indisputable evidence of an imminent danger to British interests. Even with the fanatical backing of the Murdoch press, Blair’s position on Iraq was too precarious to withstand that.

In pictures: Families of Iraq War victims react to Chilcot report Show all 10 1 /10 In pictures: Families of Iraq War victims react to Chilcot report In pictures: Families of Iraq War victims react to Chilcot report Relatives and friends of the military personnel who died in Iraq, leave the Queen Elizabeth II Conference Centre PA In pictures: Families of Iraq War victims react to Chilcot report Dawn Holmes, the mother of L Cpl Sarah Holmes who died in Iraq, is consoled by solicitor Matthew Jury as she leaves the Queen Elizabeth II Conference Centre PA In pictures: Families of Iraq War victims react to Chilcot report A family member holding a photograph of Stephen Robert Wright (R), outside the Queen Elizabeth II Conference Centre, after the publication of the Chilcot inquiry into the Iraq War PA In pictures: Families of Iraq War victims react to Chilcot report Families of soldiers killed in the Iraq conflict stand together outside the Queen Elizabeth II conference centre after the outcome of the Chilcot report Getty Images In pictures: Families of Iraq War victims react to Chilcot report Relatives of military personnel killed during the Iraq War talk at a news conference after listening to Sir John Chilcot present The Iraq Inquiry Report at the Queen Elizabeth II Centre in Westminster Getty In pictures: Families of Iraq War victims react to Chilcot report Relatives of military personnel killed during the Iraq War react after listening to Sir John Chilcot presenting The Iraq Inquiry Report at the Queen Elizabeth II Centre in London AP In pictures: Families of Iraq War victims react to Chilcot report Relatives and friends of military personnel killed during the Iraq War attend a news conference after listening to Sir John Chilcot present The Iraq Inquiry Report at the Queen Elizabeth II Centre in Westminster Getty Images In pictures: Families of Iraq War victims react to Chilcot report Family of those who died in Iraq speak to the media as they leave the Queen Elizabeth II Conference Centre in London PA In pictures: Families of Iraq War victims react to Chilcot report Relatives and friends of military personnel killed during the Iraq War attend a news conference after Sir John Chilcot presented The Iraq Inquiry Report at the Queen Elizabeth II Centre in Westminster Getty Images In pictures: Families of Iraq War victims react to Chilcot report Victoria Jones (L), a relative of a British soldier killed in Iraq, holds a copy of The Report of the Iraq Inquiry, by John Chilcot, at the Queen Elizabeth II centre in London Reuters

Gordon’s effort to blame American secrecy demeans him. He who knew every nook and cranny of that government knew that Peter Goldsmith, the Attorney General, was being put under colossal pressure to reverse his opinion about the war’s legality.

He knew from Hans Blix that the WMD case against Saddam Hussein was weak and unproven. He knew the real casus belli, as stated by Bush, was regime change. He knew there was no coherent plan for after Saddam’s fall. He knew, or should have known because almost every informed voice was saying so, that the aftermath would be as long, difficult and chaotic as the war itself would be quick, easy and orderly.

Despite knowing all that, this ferocious man of destiny sat meek and silent in Cabinet watching the calamity unfold in super-slow motion.

Others did the same, and they are equally guilty under the doctrine of collective responsibility. But they were pitiable cowards in an administration so dominated by its warring duumvirate that there was barely enough oxygen around the cabinet table for the pygmies.

Gordon’s motive for colluding with Blair by omission was a different form of cowardice. He wasn’t frightened of losing the job he had. He was terrified of losing the job he craved. The internal battle was the classically tragic one between good intentions and rampant ambition. The latter won. The potential for greatness was shrunk by the greed for power.

Odious abuses of power at Westminster are currently exposed on a daily basis. Nothing diminishes them by comparison, but this puts them in perspective. Iraqi civilians and British troops died and grieved and suffered monstrously because some MPs abused their power to save their country from a neo-colonial folly by not using that power at all.