Can you become a billionaire by accident? It seems unlikely. Surely wealth of that kind has to be fought for and won against almost impossible odds. Billionaires, you might think, should be imposing figures, battle-hardened veterans from the financial world.

But if you had asked other diners at The Jam Factory in Oxford on a recent, damp lunchtime to pick out the billionaire in the room, I doubt they would have pointed to the FT’s guest, Jeff Skoll. Slim, slight even, with flyaway brown hair and a short stubbly beard, he looked more like a young academic or artist than a corporate titan. The taller, more heavily built gentlemen (a press officer and some other suited figures) who had arrived with him and gone to sit at a corner table, looked more the part.