Building on the supported housing model, Housing First, as developed by Dr. Sam Tsemberis in New York, was focused on homeless people with a severe mental illness ((Tsemberis, S. (2010) ‘Housing First: Ending Homelessness, Promoting Recovery and Reducing Costs’ in I. Gould Ellen and B. O’Flaherty (eds) How to House the Homeless Russell Sage Foundation: New York.)). Housing was provided ‘first’ rather than, as in the staircase model, ‘last’. Housing First offered rapid access to a settled home in the community, combined with mobile support services that visited people in their own homes. There was no requirement to stop drinking or using drugs and no requirement to accept treatment in return for housing. Housing was not removed from someone if their drug or alcohol use did not stop, or if they refused to comply with treatment. If a person’s behaviour or support needs resulted in a loss of housing, Housing First would help them find another place to live and then continue to support them for as long as was needed. Rather than being required to accept treatment or complete a series of ‘steps’ to access housing, someone in a Housing First service leaps over the steps and goes straight into housing. Mobile support is then provided to help Housing First service users to sustain their housing and promote their health and well-being and social integration, within a framework that gives service users a high degree of choice and control (Figure 1). 1-2-staircase-services Figure 1: Summarising the differences between Housing First and Staircase Services((Tsemberis, S. and Henwood, B. (2013) Housing First: Homelessness, Recovery and Community Integration. In V. Vandiver (ed.) Best Practices in Community Mental Health: A Pocket Guide, pp. 132-150. NY Oxford University Press)) In the late 1990s, pioneering American social research by Dennis P. Culhane and colleagues showed there was a small group of people with very high needs, who made long-term and repeated use of homelessness services, yet whose homelessness was never resolved((Kuhn, R. and D.P. Culhane. “Applying Cluster Analysis to Test a Typology of Homelessness by Pattern of Shelter Utilization: Results from the Analysis of Administrative Data” Departmental Papers (SPP) (1998). Available at: http://works.bepress. com/dennis_culhane/3)). Staircase services were found not to be performing well in ending this long-term (“chronic” and “episodic”) homelessness((Pleace, N. (2008) Effective Services for Substance Misuse and Homelessness in Scotland: Evidence from an International Review Edinburgh: Scottish Government – http://www.gov.scot/Resource/Doc/233172/0063910.pdf)), which was being found to be very damaging to the health and well-being of the people experiencing it((Culhane, D.P, Metraux, S., Byrne, T., Stino, M. and Bainbridge, J.”The Aging of Contemporary Homelessness” Contexts, in press (2013). Available at: http://works.bepress.com/dennis_culhane/119)). Housing First, which research showed had been successful in New York, could, in contrast, end long-term homelessness at a much higher rate than staircase services((Tsemberis, S. (2010) ‘Housing First: Ending Homelessness, Promoting Recovery and Reducing Costs’ in I. Gould Ellen and B. O’Flaherty (eds) How to House the Homeless Russell Sage Foundation: New York; Padgett, D.K.; Heywood, B.F. and Tsemberis, S.J. (2015) Housing First: Ending Homelessness, Transforming Systems and Changing Lives Oxford: Oxford University Press.)). The systematic use of comparative research, demonstrating Housing First in comparison with other homelessness services, encouraged wider use of Housing First throughout the USA and attracted attention from the Federal government. Importantly, there was also an economic case for Housing First. This case centred on the relatively high cost of frequent hospitalisation and incarceration associated with long-term homelessness, i.e. long-term homeless people often made frequent use of emergency medical services, had high rates of contact with mental health services and could often have contact with the criminal justice system. As they did not resolve long-term homelessness in many cases, staircase programmes started to be seen as not cost-efficient, especially because the staircase services themselves were also relatively expensive. Research was showing that Housing First could potentially deliver significantly better results, for a lower level of spending, than staircase services((http://www.york.ac.uk/media/chp/documents/2008/substancemisuse.pdf)). Comparatively, Housing First cost significantly less than other services. Figures from Pathways to Housing show programme costs of $57 per night, compared to $77 for a place in a shelter (approximately €52 compared €70, 2012 figures)((Source: https://pathwaystohousing.org/housing-first-model)). In London, in 2013, one Housing First service was found to cost approximately £9,600 (€13,500) per person per year (excluding rent). This was compared to between £1,000 per year more for a shelter, or nearly £8,000 more for a place in a high-intensity staircase service (excluding rent). This represented an annual saving approximately equivalent to between €1,400 and €11,250 (2013 figures)((Pleace, N. and Bretherton, J. (2013) Camden Housing First: A ‘Housing First’ Experiment in London York: University of York https://www.york.ac.uk/media/chp/documents/2013/Camden%20Housing%20First%20Final%20Report%20NM2.pdf)). It was also seen that by ending homelessness among people with very high support needs, Housing First could potentially save money for other services, such as psychiatric services, emergency medical services and the criminal justice system. This was because homeless people with very high support needs, if they were housed with the proper support, would not encounter these services as often as when they were homeless and could stop using them altogether((Culhane, D.P. (2008) The Cost of Homelessness: A Perspective from the United States European Journal of Homelessness 2.1, 97-114 – http://housingfirstguide.eu/website/wp-content/uploads/2016/03/The-cost-of-Homelessness-Aperspective-from-the-United-States.pdf Pleace, N.; Baptista, I..; Benjaminsen, L. and Busch-Geertsema, V.. (2013) The Costs of Homelessness in Europe: An Assessment of the Current Evidence Base Brussels: FEANTSA http://housingfirstguide.eu/website/wp-content/ uploads/2016/03/feantsa-studies_03_web-Cost-of-Homelessness.pdf)). Homeless people with high support needs could now be offered Housing First, which, as well as being very likely to end their homelessness, could be more cost effective than alternative homelessness services((Pleace, N. and Bretherton, J. (2013) The Case for Housing First in the European Union: A Critical Evaluation of Concerns about Effectiveness European Journal of Homelessness, 7(2), 21-41 vid supra)).