The brief window in which it was cool to be an Etonian has closed. That period was marked not just by Etonian success and visibility – in politics, on the stage, in the media, even on the balcony of Buckingham Palace – but also by a new-found unabashedness in expressing pride at having attended King Henry VI’s Thames-side ­college, founded for 70 poor scholars in 1440. David Cameron summed it up when he said he was “not embarrassed” that he had gone to “a fantastic school . . . because I had a great education and I know what a great education means”.

All this was quite strange and ­perturbing to me, as an alumnus of an older era, the 1970s, when being an Etonian seemed decidedly uncool. When asked which school we had attended, my contemporaries and I muttered that we had been to a comprehensive near Slough. It was perturbing because I always had my doubts about Etonian confidence, or arrogance.

The closing of this window can be dated precisely to the early hours of the morning of 24 June. At that moment, it became clear that David Cameron had taken an insouciant, arrogant and disastrous gamble, in the interests of maintaining Conservative Party unity, by calling an unnecessary referendum on Britain’s membership of the European Union that he believed he was sure to

win. The window closed even more tightly a week later, when Boris Johnson, having helped to lead the Leave campaign, suddenly declared that he was no longer standing for the Tory leadership – the glittering prize for which he had apparently abandoned his principles and betrayed his friends.

If the Battle of Waterloo had been won on the playing fields of Eton, it now appeared that Britain’s relationship with Europe, and even its continued integrity as a nation, had been wrecked there. It was no surprise that there should be a turning against Eton, with gleeful opinion pieces from the left-leaning commentariat mocking everything from Tom Hiddleston’s backside to the commitment to public service of one of our ablest MPs, Jesse Norman.

I find this reaction as shallow as the ­excessive pride that preceded it. Maybe that is not surprising, as I both love and feel dissatisfied, even disappointed, by the school where I spent five years of my boyhood and then two and a half years teaching English literature as a young adult. The feeling of let-down is more than personal. Eton has something to answer for, at a national level. A few years ago, I wrote these words: “I’ve often wondered whether this famous Eton confidence could be skin-deep: certainly people such as Boris Johnson and David Cameron do not lack chutzpah, but the confidence to believe you deserve the high position does not necessarily mean you possess the other talents – humility, for instance, and the ability to listen to others – needed to honour it.” Now the 11 Eton pupils who managed to secure an interview with Vladimir Putin have trumped even Cameron and Johnson

in the chutzpah department, but not necessarily added lustre to their alma mater.

I had a chance to reassess the ambivalence I feel about Eton, and to reflect on the role that this ancient and eccentric place has played in our national crisis, when I attended a reunion at my old school just three days after the dark night of 23 June.

This was not a reunion of old boys but a celebration of the 50th anniversary of the Eton English department, an institution for which I feel affection and profound gratitude. As a boy, I was inspired not only to read voraciously and widely – the novels of Thomas Hardy, Henry James, Dickens, William Faulkner; the poetry of Coleridge, Wordsworth, Emily Dickinson, T S Eliot, Charles Causley, Louis MacNeice, Henry Vaughan; Shakespeare at his most intense – but also to analyse, think and feel simultaneously. Alan Paton’s Cry, the Beloved Country and Dickens’s Hard Times opened my eyes to conditions as far from my comfortable Home Counties upbringing as you could imagine, to the realities of racial segregation and working-class ­deprivation; opened my heart, too, I hope.

I was being challenged to reflect on my privilege, even be discomfited by it – not just blindly perpetuate it.

For those reasons, I was honoured to be invited back to teach, initially for just a year, in the department that had given me so much mind-and-soul nourishment. I was not the most confident or organised of teachers, but pupils I bumped into years later said they had enjoyed and gained something from classes in which discipline was not always the tightest. A debate I set up to discuss the miners’ strike turned into a riot. Above all, I enjoyed directing motivated and talented boys in productions of Journey’s End and Death of a Salesman which moved audiences.

***

Inspiration, warmth and a streak of anarchy are, perhaps, not the qualities you associate with Eton. But they were present in the English department, which started as a sort of anti-establishment challenge to the hegemony of classics. Angus Graham-Campbell, my laconic head of department, summed up the department’s signature virtues as scholarship, exuberance and irreverence.

The English department was not exactly typical of Eton as a whole. It was, I suppose, the haven for sensitive and artistic souls, for subversives and mavericks. Eton had other, for me less attractive, sides. I particularly disliked Pop, the self-elected club of prefects who strutted their stuff and lorded it over underlings in brightly embroidered waistcoats – the club to which Boris Johnson (but not David Cameron) belonged. This was more Game of Thrones than “The Love Song of J Alfred Prufrock”.

Eton, above all, was intensely male, intensely hierarchical and intensely competitive. Like Boris, I was a King’s Scholar; successors of the original 70 poor scholars, we lived apart from other Etonians in ancient quarters close to the 15th-century chapel, wore gowns and competed more for academic honours than for social kudos. Like Boris, I won the Newcastle Scholarship in classics and divinity, a strange 19th-century leftover that involved composing verses in Greek iambics, reading the Gospel of Matthew and the Acts of the Apostles in Greek and answering a paper on the doctrine of the Atonement – all in the term before A-levels.

I was proud of my academic achievements. But having had a chance to reflect on the Etonian male culture of competition from the outside, and then seeing it from a different angle when I went back to teach there, I began to doubt how healthy it was. I realised that coming top of the form and winning prizes had mattered far too much to me. It had even affected my choice of A-levels; I was good at classics and felt fairly confident of being the biggest fish in that smallish pond, rather than swimming in the broader waters of history and modern languages. Surely what mattered was finding yourself, your passion and your vocation?

I was artistically minded and Eton provided wonderful opportunities in drama (the groundwork was being laid for the flowering of acting talent we have seen recently) and music; but “creative writing” and painting, encouraged up to the age of 14, were suddenly put away as childish things when you reached adolescence (this, mind you, is not unique to Eton). From the age of 15, I never even considered choosing to go to music, art or drama school rather than taking the well-worn path to an Oxbridge scholarship. Achieving that seemed to be the pinnacle of Etonian success, and the only thing my worldly housemaster ever cared about.

Certainly no one talked much about happiness or emotional health. Eton’s pastoral care seemed close to non-existent. I kept my unhappiness to myself, with unhelpful consequences. For four of my contemporaries in college, who committed suicide in their late teens or twenties, the consequen­ces were more dire.

This may be sounding too much like a personal lament, or a reprise of Cyril Connolly’s theory of permanent adolescence in Enemies of Promise. I found my way eventually to what I wanted to be and do (it involved a lot of psychotherapy and a wonderfully liberating year in Barcelona). But I think my criticisms of Eton have a bearing on our national tragedy.

The atmosphere at the Eton English department celebration a few weeks ago did not lack the appropriate exuberance and irreverence, and the setting in the provost’s garden, surrounded with sculptures by Rodin, Jacob Epstein and Henry Moore, was exquisitely beautiful. Yet I could not help sensing the unquiet ghosts of Dave and Boris stalking the corridors behind us. I imagined them locked in an immature male rivalry that has ended up inflicting incalculable damage on a nation. Now Dave has decided to quit the political stage, leaving rather little in the way of legacy behind him.

Perhaps Boris, the King’s Scholar, could not forgive Dave for winning the ultimate prize. However, in taking revenge, he found himself hoist with his own petard, before somehow managing to emerge with a lesser prize, which some see as a ­poisoned chalice.

It all made me think of that supremely pointless sport, the Eton wall game. I played once or twice before giving up, repelled by the sheer unpleasantness of being ground into either brick or mud, and the tedium of a game in which the last goal had been scored in 1909. As a Colleger, though, I supported our team of brainboxes, drawn from the 70 scholars to play against the brawn of the Oppidans (the rest of the school, 1,200 of them). No doubting that it was antler-to-antler stuff, or like the contests of male musk oxen that knock each other senseless.

Eton remains archaic in its attitude towards women. It is still a boys-only boarding school (though a small number of girls, mainly the daughters of teachers, have been pupils there), and the staff are overwhelmingly male. Being largely cut off from women and girls for much of your boyhood and adolescence does not seem to me an ideal recipe for emotional health, or for regarding women as equals.

The school that has educated 19 prime ministers may provide a brilliant academic education and countless other opportunities, but it can leave its pupils emotionally floundering behind a façade of polish and charm. The effects of that emotional impoverishment can be far-reaching indeed. I am encouraged that the new headmaster, Simon Henderson, has signalled a change of tone at Eton, with more stress on “emotional intelligence” and “mental health”. That change is long overdue.

Harry Eyres is the author of “Horace and Me: Life Lessons from an Ancient Poet”, published by Bloomsbury