David Kynaston is a historian who has written books on postwar Britain, the City of London and cricket. His latest book, co-written with his old cricketing friend Francis Green, is called Engines of Privilege: Britain’s Private School Problem, and focuses on the unfair advantage offered by the independent education sector.

You are known for your forensic histories of modern Britain. What inspired this book?
It’s an issue I’ve become deeply interested in since my sons went to a state grammar school in 2007. They both played football for their school and standing on the touchline when they played against local private and state schools I saw the full spectrum of the unequal allocation of resources, the huge difference in the quality of facilities at state and private schools. The unfairness hit me terribly hard. A few years later in 2014 I gave the Orwell lecture, focusing on the private school question, and then at the end of that year my son George and I wrote a piece on the history and cultural significance of private schools in the New Statesman, which provoked five further articles the following week. That was the moment that made me think this was an issue that had some traction.

You argue that private schools add significantly to a child’s socioeconomic opportunities. What do you think would have happened to you, had you not attended Wellington college?
If one has had a very privileged education and then one achieves anything in adult life, there’s always that nagging thought – how much is down to the fact that one had good fortune and others didn’t? The academic advantages conferred by the private school are not dramatic but significant, and cumulatively over the course of a childhood they amount to quite a lot.

What tangible advantages did going to private school give you?
In my case, boarding school provided an escape from my parents’ divorce. I was nine when it happened and school was friendly and cosy and it was nice to have another world to go to. Later, I had three very good history teachers and they really got me flying intellectually. In some ways I had better history teaching at school than I did when I was at Oxford. But perhaps the most important thing it gave me was confidence. Private-school students are taught that they are going to do well in life. That makes a huge psychological difference growing up.

There has been a discussion about reforming private schools for decades. Why has it not got anywhere?
I think the liberal left find it a difficult issue because parents want to do the best for their children and if they can afford it they’ll often educate their children privately, and that’s entirely understandable. But attitudes become very entrenched when people have made a significant financial investment. And if one’s been privately educated oneself there’s the question of having advantages that others have not had, and then throwing away the ladder one’s climbed up oneself.

Do you think anything will change in your or your children’s lifetime?
It’s not impossible because I believe that plates shift in history in a way that is often beyond the control of individuals. There was something plate-shifting about the 1945 election, which brought in the welfare state. I think the plates shifted again at the end of the 1970s and the Thatcher/Reagan era. Now, particularly since the financial crash, we are approaching the end of free-market orthodoxy and there is an anti-privilege mood around. It is hard to see how the private schools can escape from this unscathed.

Should we bring back grammar schools?
It is an important question and I am a bit conflicted. When grammar schools were phased out at the end of the 1960s, something was lost. At that point, they were offering real academic competition to the private schools. But you also had the problem of selection, division within families and three quarters of the population being written off. I think overall there was a good case for abolition but it was a debatable case. I am not nearly as unsympathetic towards grammars as I am towards private schools.

What should be done now?
There’s obviously the question of outright abolition, but in our view to aim at that is impractical because it would be such a difficult thing to achieve. My starting point is where we are at the moment, with these highly resourced schools for, on the whole, children of wealthy parents, entrenching already existing advantages. So anything, in a sense, is better than where we are now. We’ve put our emphasis on changing the social composition of the schools. We call for a fair access scheme in which, initially, 33% of pupils at private schools would be state-subsidised.

Have you had any interesting reactions to your book so far?
Not yet, but I honestly do not know what to expect when it is published next month. We have tried to write it in a moderate way, keeping it evidence-based and non-agitprop, not attacking parents or making futile accusations of hypocrisy. If a lot of personal shit and mud gets thrown then I will be very sad because that is not the spirit in which the book is written. We are a mature democracy but we are not always able to talk about this subject in a mature way.