This Russian-born fintech tycoon came to the UK when he was 20 and worked as a trader for Lehman Brothers, losing around £500,000 when the firm collapsed in 2008. Seven years later he launched Revolut, an app-based payments service undercutting mainstream banks with services such as fee-free foreign exchange. Storonsky was also quick to offer cryptocurrency trading services, attracting millions of new customers as conventional lenders bided their time. Revolut now operates across 160 countries and has attracted more than 40 million customers.