Online lender Wonga has achieved another year of strong growth after topping last year’s Tech Track 100: it has expanded into South Africa and now offers small business loans in Britain. Founded in 2006 by chief executive Errol Damelin, Wonga has hit back at accusations of “legal loan sharking” saying it is completely transparent and that 80% of users would recommend it. The London firm’s backers include Balderton Capital, Accel Partners, the Wellcome Trust and early-stage investor TAG. Sales, which consist of interest and fees, grew 245% a year, from £4.5m in 2008 to £184.7m in 2011.