I am of course referring to his tweet "I’ve heard if you earn minimum wage in England you’re in the top 10% earners in the World. #stay #humble’".
This is what the Institute for Economic Affairs has to say: "over half the world's population has an income of less than $5.70 a day. And as Tim Worstall has pointed out, someone working full time (say, 37.5 hours a week) on the minimum wage would earn £12,675 a year. This puts them in the top 6.41% of the global income distribution, according to this calculator which converts in purchasing power parity terms. This is before incorporating the tax and benefits system, which combined are highly progressive. Since the distribution on that website is in net income terms, we might imagine then that many people earning the NMW plus state top ups are higher still in the distribution."