An accelerator for start-ups with a social purpose has raised £1.3m to expand its programme and create a larger fund for early stage businesses. Bethnal Green Ventures, whose programme develops technology companies looking to solve a social problem at the same time as making a profit, has secured the investment from Big Society Capital, Nominet Trust and Nesta. In its fifth year, the London-based accelerator will use the cash to bring more start-ups on to its programme and provide follow-up capital to its most promising graduates. The round marks the first time that Big Society Capital, an investor in charities and social enterprises, has backed an accelerator. It brings the organisation's total funding to date to almost £3m. "It's a ringing endorsement of our model and tech for good," said Paul Miller, partner at Bethnal Green Ventures. "We need to grow to meet the demand of increasing numbers of applications, as well as more and more start-ups growing so quickly that they need further capital." Bethnal Green Ventures' success stories include Dr Doctor, an NHS appointment management system saving seven NHS trusts around £1.2m a year and ethical smartphone manufacturer Fairphone, which has sold more than 125,000 devices and has a turnover of more than €15m (£13m).