At 21 years old, Gary Stevenson joined Citibank as its youngest trader. Three years later, he became the bank's most profitable trader by betting on the collapse of the economy. He went from living in his parents' two-bed terrace in east London to earning millions. But it didn't feel right to make money betting on disasters. So, he quit, leaving his dream job in the City to campaign on the issue of wealth inequality. He tells James why our obsession with money is destroying the things that matter. Gary's new book, The Trading Game: A Confession is out on 5th March.