It all started when Scotland Yard arrived in a house in Hounslow, on the western fringes of London, where Nav Sarao was arrested on one late April morning. Wait, this wasn't some dramatic perp walk out of a glass tower in Canary Wharf? No, for one simple reason: Sarao lived his parents. He also didn't know how to drive. And so begins one of the most fascinating profiles of a modern day financial mastermind: instead of tailored Saville Row suits, thundering parties, booming Bugattis and the occasional jaunt to the Riviera, Nav was the antithesis of a Wall Street. He was, in the words of Bloomberg which has created a fascinating profile of the young trading guru, "pathologically frugal" in fact "Sarao was so frugal it was almost an eccentricity."