Sir Ronald Cohen, non-executive chairman of Big Society Capital, today said that "impact investment" is necessary in order to solve pressing social problems, at a time when governments "are out of cash, and out of breath, in dealing with social issues".

He said: "What we need to achieve here is the definition of an asset class, where a pension fund, for example, would say 'we need to invest 2-3%'" of assets in social investment projects.