Two days before Britain voted to leave the European Union, Shanker Singham wrote an article arguing in favour of Remain. Yet today he is busy promoting what he calls “the Brexit opportunity”.

Why did Singham, one of the world’s leading trade and competition lawyers, change his mind? I’ve come to his offices in Mayfair to find out. But also to discover more about another, even more profound conversion.

Singham works at the Legatum Institute, a think tank “promoting policies that lift people from poverty to prosperity”. On this, the hottest day of the year, we retreat to an air-conditioned library several floors up.