Getting millions of people every day to pay £3 for a cup of coffee in a cardboard cup surely has to be one of the biggest of our time

Just read the whole wiki article on Charles Ponzi.  A fascinating read.  The denouement is great:

Supported by his last and only friend who spoke English and had notions of Italian, the barber Francisco Nonato Nunes, Ponzi granted one last interview to an American reporter, telling him, "Even if they never got anything for it, it was cheap at that price. Without malice aforethought I had given them the best show that was ever staged in their territory since the landing of the Pilgrims! It was easily worth fifteen million bucks to watch me put the thing over."