As I enter the porter’s lodge at St Hugh’s College, Oxford, I fleetingly reflect that I may be about to receive an intimidating tutorial from the college principal, Andrew Dilnot. It is not that the economist has a stern reputation, but today’s circumstances are unusual. He recently stepped down from presenting More or Less, a BBC Radio 4 series about numbers in the news. I have been recruited as the new presenter, and am ready to be patronised – or worse.

I needn’t have worried: as he strides into the lodge in a pale brown linen suit and blue tie, Dilnot’s smile is genuine enough, and as we walk together through north Oxford’s leafy residential streets, he is more eager to identify shared acquaintances in the world of economics than to lecture me on the art of radio presenting.