This report makes the case for all local agencies (local authorities, the police, health services and others) to examine what they spend on troubled families, how they spend it, and how effective that expenditure is in helping turn lives around and preventing the emergence of future troubled families. Public services cannot afford to spend their resources ineffectively when reacting to the social problems of these families. With the economic challenges that the country currently faces there is an even more powerful impetus to ensure this is not the case. Of course there is a huge human cost of failing to intervene effectively with troubled families – and this has been set out in the two previous reports from the Troubled Families Team. However the financial costs are also important to understand and evaluate. There are figures and examples in this report that make this case starkly. We spend disproportionately more on troubled families than the ‘average’ family. For example, in West Cheshire, the council is spending an average of £7,795 on an average family in its area, compared to £76,190 for a troubled family. In Solihull, local services spend an average of £5,217 on an average family, compared with £46,217 on a troubled family. The amount spent on a troubled family is estimated at nearly £100,000 in Barnet. This is not sustainable. While not all of these costs can be averted, the projected financial benefits of investing a comparably small amount in family intervention services are compelling. For example, in Leicestershire, the council is projecting average savings of around £25,700 per troubled family, in West Cheshire, the local authority is estimating savings of around £20,000 per troubled family and in Manchester, the city council is estimating savings of around £32,600 per troubled family. In the London Borough of Wandsworth, the council is making early stage projections of around £29,000 worth of savings. For just the prison service’s costs alone, the family intervention service in Hull has saved an estimated average of £6,829 per troubled family. Although calculations are at an early stage, savings of this sort scaled up to a national level would run into billions of pounds. While this report documents valuable work laying the foundations of increasingly more rigorous local financial cases for investment in new ways of working, we do not underestimate the challenges faced and the degree to which this remains very much a work-in-progress for all areas. Just as the Troubled Families Programme presents a considerable delivery challenge, getting under the skin of the costs and potential financial benefits of this work is a big ask. Just as families’ problems fall across multiple areas of need, the expenditure on them falls across multiple parts of the public sector (both locally and centrally). Accessing, understanding and applying information from these sources, gaining political and strategic traction within their often-competing priorities and being able to achieve the holy grail of ‘cashing’1 some of the projected financial benefits are daunting tasks. This report showcases some of the early work that local authorities are undertaking to address these challenges and bring together the necessary evidence and local support. This is pioneering work of national significance and of great value to other public sector agencies, which share a desire to spend taxpayers’ money more efficiently – and improve the prospects of some of the most vulnerable people in our society.