Compared with 7% of the population who went to private school (in the UK known as “public” schools, for historical reasons), 50% of doctors did, with the proportion not budging these past 20 years. Does it matter? Couldn’t private school attendance just be a marker for academic ability, with potential medical students needing high grades to get accepted?

It’s not as simple as that. As pointed out in the BMA’s recent report on equality and diversity in UK medical schools, a state school student has the same chance of going to one of the UK’s leading 13 universities as a student from the independent private sector who gets two grades lower at A-level. Private schools give their lucky students a “leg up.” After university, ex-public school boys and girls dominate all the professions.

So are public schools a blight on British society? That was the motion debated at an evening organised by Intelligence Squared on 3 February. First off was ex-Harrovian journalist Francis Wheen, “who would sooner eat Piers Morgan’s vomit than send his children to public school.” He railed against a great many things, including the £100m tax breaks enjoyed by private schools as charitable institutions, “reparations” exacted from the little people to keep their betters on the fast track.

Barnaby Lenon, headmaster of Harrow, predictably sang the praises of a private education. And he didn’t ask us just to take his word for it. PISA, an outfit that rates educational achievement in 43 OECD countries, places UK public schools top. Some 10 000 children fly in to the UK for private education each year, he said. Most UK public schools have been approached to roll out franchises in other countries. Many do so. Public schools aren’t as socially homogeneous as most critics assume; 45% of students didn’t have parents who went to public school; one third receive some form of financial support.

Martin Rowson, Guardian cartoonist and scourge of the Thatcherite attack on the dignity of the working class, was sickened by the complacent sense of entitlement radiated by the products of public schooling. And where did these wonderfully rounded individuals end up?  Media, law, and banking  – was the triumphant answer.

Mary Beard, Cambridge classicist, was an uncomfortable member of the team arguing against the motion. She could see how public schools entrenched snobbery and privilege and kept finding common cause with her opponents, even in her summing up. But in the end she was a classics teacher. State schools were abandoning the teaching of classics hand over fist, not to mention the teaching of modern languages, which meant almost as much to her. She had to throw her lot in with the side that was preserving the culture of humanity, she concluded, if only for the time being.

David Aaronovitch, Times journalist, made the best contribution. What are fee paying schools for? he asked. Their function is to prevent downward mobility. Ideally, they’d guarantee your children a job as good as yours if not a bit better. The trouble is if there’s upward mobility there must be downward mobility as well. School fees buy your offspring competitive advantage in the job market. As someone commented, quoting Alan Bennett, “it’s not fair.”

Felip Fernandez-Armesto, historian and Charterhouse teacher of long ago, spoke against the motion. While his oratorical flourishes were breath taking, I couldn’t divine any take home message (other than that public schools are a good, if not the very best, thing). My problem, rather than his.

The contributions from the floor were good. Someone asked that if the advantages of nourishing the mind were so great, why couldn’t they be open to all. Someone else pointed out that public schools teach 7% of the country’s students with 14% of the teachers. Far too near the end we learnt that public schools are inimical to equality and should be resisted on those grounds alone. Harrow’s website apparently says that 85% of its students previously attended (fee paying) prep schools. And an appreciable proportion of those will have attended fee paying feeder schools to get them into these prep schools. What proportion of the population could afford to give their children that “leg up”?

Before the debate, of the 1251 people who recorded an opinion, there were 32% in favour of the motion that public schools were  a blight on British society. Some 47% were against and there were 21% don’t knows. After the debate the figures were 35%, 59%, and 5%, respectively.

Tony Delamothe is deputy editor, BMJ.