An impact investment fund said to be the largest in the UK has raised a final total of £56.8m for the lettings arm of the homelessness charity St Mungo’s Broadway to house homeless people and families in London.

The Real Lettings Property Fund began raising capital in late 2012. It provides money to Real Lettings, a social lettings agency set up in 2005 that donates all profits to St Mungo’s Broadway. The fund is managed by the social investment firm Resonance, which says this is the UK’s largest such fund.

The fund was closed to investors last week, with final investments totalling £10.3m being made by Croydon Council, the charities Trust for London and Panahpur, and one high-net-worth individual. Previous investors have included the social investment wholesaler Big Society Capital, the City of London, the charity the Esmée Fairbairn Foundation and the housing association L&Q.

Since the fund was launched in 2012, more than 240 properties have either been bought or are in the process of being bought to house people who are either homeless or in danger of being homeless.

Susan Fallis, director of Real Lettings, said: "Reaching this level of investment shows that the Real Lettings Property Fund model of social investment works. Since the fund started, we have been able to help more people escape homelessness by providing a secure tenancy and support from our social lettings agency."

Simon Chisholm, investment director at Resonance, said: "The fund combines financial returns to investors with a focused social impact, breaking down barriers for those ready for independent living but excluded from the private rented sector. The successful final close at nearly £57m has proven that it can be scaled up effectively. We have done work to show that this model could be effective in other areas and we are now close to launching further similar initiatives with other local authorities across the UK."