It’s fun to look for what’s missing in a memoir; the forgotten egos, the policy howlers buried for posterity. Some omissions are accidental. When Tony Blair published his autobiography in 2010, he raised eyebrows by neglecting to mention his celebrated blue-skies thinker, John Birt. Over more than 700 pages, For the Record is punctilious and dutiful in name-checking the many fallen Cameroonian foot-soldiers who sacrificed themselves in the cause of Conservative modernisation.

It is a testament to David Cameron’s great qualities — his quick wit, habitual cheeriness and calmness under pressure — just how many of them there are. No one working in No. 10 expected to become close pals with the PM; perfectly happy in his own skin, with a young family to which he was devoted and long-standing friends of his own, he had little need to forge personal bonds with the courtiers, most of them ten to 20 years younger, who crowded into his study for the 8.30 a.m. and 4 p.m. meetings. But he and George Osborne did inspire strong and lasting loyalty both to themselves and their project.

A few loyalists have been unfairly left on the cutting-room floor. Top of my list is Daniel Korski, one of the most kinetic special advisers in the No. 10 Policy Unit. Of all the people who knew how to move fast and break things across Whitehall, DK was in a class of his own and warrants an appearance in any bonus material provided for the paperback edition. It is also odd that Chris Lockwood and Camilla — now Baroness — Cavendish, respectively my cerebral deputy and brilliant successor as head of the Policy Unit, have so far not troubled the index compilers.

Other oversights are surely more deliberate. The book lost weight on early drafts, but remains fatter than Blair’s, despite covering a premiership that lasted about half the time. It’s a good read, but could have been tighter. It manages extensive discussion of the Big Society — remember that? — but there’s not a word on the hostile environment the Home Office was actually creating. We have acres on long-forgotten summits, G8s here, G20s there, but only one short paragraph on the daft and now abandoned net migration target that raised the salience of the issue on which Ukip thrived. And there are too many irritating references to ‘the country I love’.

Eton, where Cameron spent five years in the footsteps of his father, grandfather and great-grandfather, is dispatched in three quick pages. DC says his O-level results were ‘distinctly mediocre’. No mention of the amazing fact that, notwithstanding literally the most expensive education money can buy, our future prime minister chalks up only a C in maths. Thank God the idea that we should judge someone’s fitness for office on how they did in some exams aged 16 is today seen as utterly absurd. Dope, the Buller and Oxford are all breezily dealt with by page 30.

For the Record takes us back to a world that feels decades away, in which Cameron could survey the political scene and see plenty of reasonable, rational and decent people who shared his liberal outlook and easy manner. The political partnership he forged with Osborne, ‘the most convinced and most convincing moderniser’, became Cameron’s greatest asset as prime minister. The fact that he and the Lib Dem leader Nick Clegg had similar temperaments, values and world views made it easier for them to form a historic coalition when crunch time came. Dave, George and Boris were one-nation Tories whose speeches were ‘virtually interchangeable’.

Some of the most delicious moments come when we meet people who don’t conform, such as the ‘outdated old clunker’ Iain Duncan Smith, who as leader dismayed modernisers by doing things like whipping the party against supporting unmarried couples’ right to adopt. After one particularly dismal PMQs prep session, in which IDS was ‘leaden and dull’, DC tells how Boris grabs him by the shoulders, saying: ‘Hey Dave, what’s the plan?’ Heaving him off the ground, he grunts: ‘Presumably it’s like carrying an injured hooker in the scrum — we know he can’t play, but we just pick him up and carry him over the line.’

Michael Gove gets off lightly. We watch him go from the ‘close friend’ Cameron brought into politics to someone whose motives he increasingly called into question. There is a telling moment early on when Gove pleads with DC not to run for leader. ‘I think he had nothing but the best intentions in making the call,’ Cameron says. Hmm. The biggest leaker in government, Gove was so distrusted in the building that when he was sacked as education secretary and appointed chief whip, Downing Street secretly introduced the ‘Gove Protocol’ to limit his involvement in policy making.

The biggest question hanging over For the Record, of course, is whether it offers a fair and credible account of the decision to call an in-out referendum. It’s a good effort, but I’m not sure it is wholly convincing. Cameron insists that Britain’s status in Europe was ‘becoming increasingly unsustainable, as the whole project continued to mutate into something so different from what we signed up to all those years ago’. This is obviously debatable. We had special dispensations that gave us, among other things, the unique advantage of a free ride on the single market with our own currency and monetary policy. Less sustainable than what realistic alternative?

Indeed, the modest scale of the changes that Cameron sought to negotiate and settled for ahead of the referendum does not suggest he saw any fundamental problem with the relationship. We’ve got to be honest enough to recognise that the commitment to an in-out referendum, first made in a speech at Bloomberg’s London headquarters in January 2013, was first and foremost a tool for party management after a disastrous year in which he had lost the public over the omnishambles budget, the press over Leveson, coalition unity over Lords reform and, potentially, the next general election over the failure to redraw constituency boundaries. His leadership was in jeopardy.

On Europe, the Conservative party was growing increasingly ungovernable, reflecting a broader problem in the way the EU had become the juiciest target for politicians seeking simultaneously to appeal to sceptical Tory grass roots and channel the anger of communities left behind by globalisation and technological disruption. The right had been divided, to our cost, in the UK’s 2014 European elections, in which Nigel Farage’s party won the largest number of seats, leaving the Tories trailing, for the first time, in third place in a national election. By the time Cameron actually held the referendum, the forces of populism had grown far stronger than he’d ever anticipated when he made the Bloom-berg speech.

All major political parties in the UK had at one point or other promised a plebiscite, but never actually delivered one. Whereas other European countries, such as Denmark, France and Ireland, had held referendums successfully as a kind of safety valve more than a decade earlier, we had consistently found reasons to resist. Cameron’s mistake was not so much to hold a referendum, as not to have done so earlier, over the Lisbon Treaty, before the cumulative effects of six years of austerity. The stakes would have been lower then than they were with the pressure-cooker in-out decision of 2016.

If timing was a mistake, his fatal error was to have allowed a referendum question and campaign that did not define a credible and deliverable leave option. The failure to pin down the Leave campaign to the specifics of how it would actually deliver Brexit, let alone how it would guarantee an independent trade policy, and regulatory independence from Brussels without a return to a hard border in Ireland, was one of historic proportions. It would cost him his job.

David Cameron went from MP to party leader to prime minister to private citizen in just 15 years. For the Record ends where the sorriest three and a half years in modern British history begin. Memories of his time in office for now are overshadowed by what has followed. That is unfair. He and Osborne together brought the country back from the brink. His commitment to gay marriage, to international aid and to the environment will continue to make a difference to millions at home and around the world. At a time when people wonder why anyone would want the job, this book is a helpful reminder of the good a PM can do.