BACK in the 1980s, Oxford University was like a scientist’s secret laboratory, where, in a tightly controlled environment, a new species of political animal was being created out of whatever material came to hand.

The components found at the back of the garage were certainly random: Boris Johnson, Theresa May, David Cameron, Michael Gove, Dominic Cummings. Few of them were traditional material for the very top job in the country. BoJo was a blusterer, May was diffident, Gove a bit odd, Cummings anarchic. Only Cameron, an Etonian like Boris, had the old-school qualities – a caste-iron sense of entitlement – commonly found in leaders of state.

In Chums: How a Tiny Caste of Oxford Tories Took Over the UK, an analysis of the clique that came out of Oxford at that time, Financial Times columnist and Oxford graduate Simon Kuper shows how, all those decades ago, the key players who were to lead the UK into Brexit and beyond were already as tightly-knit as the Famous Five.

It is a depressing portrait of the influence wielded by those who go to Oxford University, preferably after an education at one of the country’s most celebrated fee-paying schools. Of 16 post-war prime ministers, only four weren’t students there. In other words, if your ambition is to occupy No 10 Downing Street, Oxford is the slip road onto the political motorway, offering the fastest route.

This spectre of old-boy networks exerting disproportionate influence is nothing new. That it’s worrying goes without saying. What is even more vexing, however, is that despite awareness that far greater social mobility and diversity is the benchmark of a civilised society, this model continues to go unchallenged.

Don’t just take my word for it. A recent report by a tech platform called Zero Gravity, which is dedicated to social mobility, shows how deeply entrenched this culture remains. Its results reveal that the old boys’ and girls’ network of public schools gives students an enormous boost in terms of going to either Oxford or Cambridge, and thereafter getting into the most prestigious and lucrative professions.

Interestingly, it is not the academic credentials or amenities of these establishments that make a difference. In Zero Gravity’s words, “the main benefit of a private education is the associated spheres of influence and support that these networks facilitate”. For example, these youngsters can get help with applying for a place at Oxbridge from family friends, who are much more likely to include bankers, politicians and lawyers than is the case for state school students. They are also more likely to be encouraged to apply to a Russell Group University, and to be able to name these high-ranking institutions (for that matter, can you?). Zero Gravity’s conclusion is simple: “Our research highlights a widely accepted but rarely spoken-about truth: that who you know often matters more than what you know.”

I wouldn’t agree that this subject is not often discussed – in some households it is a bone gnawed on a daily basis, whenever the likes of Boris Johnson appears on the screen. But where Zero Gravity is right is in emphasising the disparity of life chances such privilege represents. Getting into Oxford guarantees a high-flying career. When parents shell out eye-watering sums for school fees, they are not so much buying an education as ensuring entrance to a hugely powerful elite, whose benefits will endure for the rest of their child’s life.

Altering the status quo will be no easy task. But unless you actually enjoy the taste of sour grapes, or are too busy constructing your barricades for the forthcoming revolution, there is another way of looking at the shameful class-ridden apartheid that continues to shape the way our country is run.

Think of all the jobs those from private schools would struggle to get, or never consider applying for. When, for instance, were you last attended by a nurse or paramedic who went to Eton or Roedean? I have a relative from Musselburgh, whose accent is a far cry from Fettes. Even so, she initially struggled to overcome her background when she taught in a deprived part of Edinburgh. The class thought she was super-posh, and it took a while for them to realise she was not a Rees-Mogg beamed in from a different planet, but no different from them.

Think how much harder it would be for an old Etonian or Wykehamist to fit into a workplace like this. Or to follow a career in, say, social work, where the first thing people would notice would be their plummy vowels. It would take the skills of a Benedict Cummerbatch to blend in with colleagues in this and other professions, where the work entails immersion among society’s most beleaguered. And where their pronunciation is the embodiment of an Establishment that is widely perceived as doing its best to crush them.

No doubt those who went to major fee-paying schools occasionally make this leap and go on to great things. But they are rare compared to their peers who go into the City, or the Inns of Court or the Houses of Parliament where, like starlings swarming back to their roosts at dusk, they effortlessly blend in.

This seems to me a serious shortcoming in the private educational system, where pupils’ life choices are selected for them before they are born. Public schools are driven by ambition: for status, connections, influence, but above all wealth. Ability is useful but not essential for getting on far beyond the dreams of most ordinary talented folk. As a result, those students who are not over-endowed with intellect, or are practical or artistic rather than academic, can have a hard time diverging from the group think.

I exaggerate, of course, but only to a degree. It seems to me yet another indictment of a system designed to divide and rule. Nothing about it is right or fair. Yet – and this truly is shocking – the people responsible for ensuring the domination of this class-based system are not just those who buy into it. It is all of us who secretly are impressed by the braying or cut-glass accents, by the Oxbridge degrees and venerable family piles. For some unfathomable reason, it is widely accepted that somehow these people are brighter than the rest of us, and will do things better. Well, we surely know now what a daft notion that is.

Read more by Rosemary Goring:

St Andrews deserves its title as Britain's best university

When Professor Snape muscled in on my marriage