Sasha Swire’s diaries force us to make a point against ourselves.  Never, ever assume that anything said in front of a journalist won’t end up in print, unless you’ve a specific guarantee of it (and not necessarily then).  Actually, scrap that.  Never assume that anything said in front of anyone won’t end up in print.

To judge from the extracts, the diaries are a mash-up of the perceptive and the delusional, bound together by a blithe disregard for discretion.  Which would make Swire a natural diarist.

A story, doubtless untrue, is doing the rounds.  That it was put to Hugo Swire, her ex-Conservative MP husband, that the diaries’ publication will them friends.  “I suppose so,” he is said to have replied.  “In which case, I’ll just have to buy some new ones.”

Whether apocryphal or not, that catches the flavour of the extracts: they paint a picture of a self-perpetuating elite which believed it was born to rule.  There is enough truth in the charge for the ever-alert George Osborne to have launched a salvage operation.

The case for the prosecution is that leadership in Cameron’s Conservative Party – and thus in the Tory part of the Coalition Government – was confined to a small, southern-based, privately-educated, independently-wealthy closed circle of chums out of touch with much of the public.

And it is indeed the case that the two spiky outsiders in that group, Steve Hilton and Michael Gove, eventually fell out of favour with Cameron for what seems to be the same reason: ultimately, they prized conviction above pragmatism.

His successors’ social reach is wider. In grammar school-educated Theresa May’s first Downing Street, her first two chiefs of staff came respectively from Birmingham (Nick Timothy) and Inverclyde (Fiona Hill).  Boris Johnson’s Downing Street is driven by Dominic Cummings – privately-educated, but a northerner.

The Prime Minister himself is one of the boys, who is both on much the same social page as Cameron and Osborne while also being part of a different story: that of a man who is fundamentally a loner.  This explains why he was so open to Cummings, and often to those of a very different background to himself, in the first place.

The case for the defence is that Cameron and Osborne appointed their front bench on merit, with exceptions based largely on the limited availability of women.  (Both may well now agree that the rushing through the ranks of Sayeeda Warsi, for example, was an experiment that went awry.)

After all, Cameron screwed himself up to sack his friend, Swire, as Shadow Culture Secretary – which helps to explain why his wife writes as she does.  She believes that he should have been Foreign Secretary.  But show me a politicians who doesn’t believe that he was under-promoted.  Their wives don’t always take the same view.

For the record and what it’s worth, I didn’t vote for Cameron as Conservative leader, but don’t feel for a moment that I was unfairly treated.  At the time I went out of Parliament and he went into govenment, his Cabinet included Gove, Ken Clarke, Iain Duncan Smith, Liam Fox, Eric Pickles and Owen Paterson: that’s a spread of talent.

Iain Dale suggested yesterday on this site that Cameron is loathed by Leavers for supporting Britain’s EU membership, and blamed by Remainers for holding a referendum on it.  Certainly, he trusted to his fabulous luck with referendums (think AV, think Scotland), and had no plan for the country if he lost.

But until the trauma of 2016 and the advent of Johnson, Cameron had proved himself the second most successful Conservative leader in general elections since the war, fighting two, winning one outright, and losing neither.  It is easy to forget that now.

Those names from that first Cabinet should also be a reminder that he was in many ways a good Prime Minister, getting the deficit down while reforming public services: consider the work of Gove at Education and Duncan Smith at Work and Pensions.

Swire’s diaries paint a picture of politics as a game – all about self-advancement.  However, ponder a point more easily missed than it should be.  The image of Osborne inside the Westminster Village is one of a cynical operator.  But his loyalty to Cameron was exemplary and, given the history of Prime Ministers and Chancellors, rare.

It’s worth digging a big deeper than the diary’s surface.  “You could put a snooker table in there,” Swire reports Cameron as saying of a barn in her husband’s Devon home.  After which she muttered to her husband: “so home counties”.

A snapshot of generations-worth of class snobbery?  But Swire’s father, John Nott, was an acerbic outsider in the stuffy world of the pre-Thatcher Conservative Party.  Her mother comes from outside England’s class system altogether: his wife was born in Slovenia, and her father was imprisoned in Dachau.

If Swire wasn’t in some sense an outsider herself she couldn’t have written these diaries.  Meanwhile, as Henry Hill has reported in his study of the 2019 Tory intake, Boris’ Boys and Girls, the Tory Parliamentary Party is undergoing quiet but unmissable change.

“Schooling is always one of the things Tory MPs seem to be most cagey about,” he wrote earlier this year, “but from those who have been explicit there is a similar portion of publicly-educated winners as in 2017, at around 14 per cent.”