When it comes to insight, sometimes only a woman can do the job properly. Lots of books – too many! – have been written about Brexit, each more indigestible than the last. To read the smallest excerpt of David Cameron’s self-serving 2019 memoir, For the Record, required a hearty dose of Pepto-Bismol, and even then one felt bilious. But these chunky hardbacks were, almost without exception, written by men – and men, especially those who care more than they should about power, tend not to notice the small things (that, or they refuse to deal in what they consider trivial). Their eyes on the bigger, grander picture, the telling detail inevitably eludes them.

It would be easy to take the piss out of Sarah Vine’s How Not to Be a Political Wife – and I’m about to indulge on this score myself. With its star appearances by Joan Collins and its author’s seeming belief that the only place to buy a dining table is Oka (the overpriced greige emporium founded by Annabel Astor, AKA Samantha Cameron’s mum), it comes with its own brand of ridiculousness. Vine’s insistently disdainful talk of how the “grubbier” newspapers invaded her life when she was married to cabinet minister Michael Gove is frankly deranged given she’s a columnist at the Daily Mail – by some distance the vilest paper of them all.

Still, I read it with rapt fascination, every page delivering some mini-revelation. I’m still reeling from the news that, according to Vine, in 2006, Dominic Cummings, the sinister mastermind of the Vote Leave campaign, had his heart broken by Kirstie “Location, Location, Location” Allsopp. The mind boggles. Maybe Brexit might have been avoided if Dom had been busy knocking down some wall in pursuit of another en suite bathroom. (“Our builder says it will cost £110,000, which is a lot less than the UK sends the EU every week, darling.”)

From her perch on the squashy sofas of Chequers and Dorneywood – probably not Oka – Vine observes the gang of old Oxford friends that had somehow managed to end up running the country in all their breathtaking carelessness.

Did they want to do the right thing? Sometimes, possibly. But, hey, let there be karaoke first! (One Christmas, Vine and Cameron end up together in a Slough retail park, where the prime minister buys an X Factor “official merchandise” karaoke machine for Chequers, the better that refreshed cabinet ministers might air guitar to Stairway to Heaven). In this book, no one’s reading Edward Gibbon, or even Edward Heath – with the possible exception of Vine’s husband. The Goves’ small house in a less-than-salubrious part of west London – bought for its closeness to the Cameron residence – is so heaving with fat histories, you begin to fear he’ll be killed by a toppling bookcase, like Leonard Bast in EM Forster’s novel Howards End.

Ah, yes. Michael. He and Sarah are highly civilised ex-partners – they divorced in 2022 – and thanks in part (though not entirely) to this, he emerges surprisingly well from the pages of How Not to Be a Political Wife. Impossible not to warm to a man who takes bath time as seriously as he does, a vision in a lavender dressing gown, the air about him scented with Clarins.

I read it with rapt fascination, every page delivering some mini-revelation

Like Vine, who grew up in Italy with her raffish, neglectful and sometimes (on the part of her father) verbally abusive parents, he’s not born to the world of Cameron, George Osborne et al. The adopted son of the owner of a family fish processing plant in Aberdeen and a scholarship boy to his bones, he has neither their cash – “Can’t you just ask your dad for some money?” asks Osborne, when Vine confesses their money worries – nor their temerity.

Though an instinctive leaver himself, from the outset he advises Cameron not to hold his risky referendum. Turning up at Boris Johnson’s Oxfordshire house after the Brexit vote, he is appalled to find Johnson blithely barbecuing sausages; Gove’s people are humping laptops and studying spreadsheets, desperate to plot the tricky (impossible) path ahead.

We know how this ended. Theresa May became PM, to be succeeded by Johnson, then Truss. Gove, having stood down as an MP, is now editor of the Spectator; his wife continues to howl at Meghan Sussex from the broomstick she rides as the Mail’s self-dubbed “Wednesday Witch”.

Is Vine right to suggest that by resigning immediately after the Brexit vote – a snap decision that caused chaos – Cameron ensured that it would be a disaster, like some stroppy child scattering another boy’s Lego? Tempting as the idea is, I’m not sure he was looking that far ahead. Again, the carelessness.

For Vine, the consequences were more personal. I can’t accept her conviction that politics destroyed her marriage, her friendships, her lovely life. People did these things. However, I understand – it makes me gasp – her sharp sense of betrayal. This story has more than seems probable in the 21st century to do with social class. When the outsiders Vine and Gove make their move – she from the Times to the Mail, he from backing Cameron, and therefore, quietly, remain, to supporting leave – their so-called friends quickly set the dial to Arctic.

There’s yelling in lifts and sushi restaurants. “We made Michael Gove!” huffs Osborne. Paradise – Chequers, and the Astors’ place on Jura, and giggles at the state opening of parliament – is lost. Sarah will dance with her BFF, Sam, in Ibiza no more. I would say it was good while it lasted. But that would be to lie. As even she must know now, it was a ghastly chimera, for which the entire country is still paying the price.

How Not to Be a Political Wife by Sarah Vine is published by HarperElement (£20). Order your copy from observershop.co.uk to receive a 10% discount. Delivery charges may apply