Private schools in the United Kingdom are affordable only to those on the highest incomes. But surprisingly to many, this is not true across developing countries, where low-cost private schools are ubiquitous and affordable to all. For nearly two decades I’ve been researching this phenomenon. I’ve visited low-cost private schools in more than 20 countries, from the vibrant slums of sub-Saharan Africa and South Asia to remote mountain villages in South-east Asia and the gang-dominated barrios of Central and Latin America.

Imagine Peace. These were the words that appeared on an otherwise blank page in the New York Times on New Year’s Day 2013. They were paid for by Yoko Ono and they are of course an echo of John Lennon’s most famous song. A few days later, the Guardian conducted an opinion poll in which it asked its readers whether they thought the advert would produce world peace. Surprisingly, a third of the respondents thought that it would, though there was little evidence around the world to confirm them in that hope.

One programme that still shines out as a beacon of intellectual rigour among the sea of dross on television is University Challenge. As always, teams of four students from Britain’s best universities battle it out for the series championship. Rather than assuming the viewer is an idiot, like most factual programmes, it works on the basis that we have a shared culture. There are always questions on kings and queens of England, Shakespeare and classical music.