This paper evaluated the mixed tenure housing policies in the UK that are based on the premise of generating social cohesion, specifically focussing on the Mixed Communities Initiative 2005. The Mixed Communities Initiative 2005 (MCI) developed by the Department for Communities and Local Government was set up as a policy approach implemented through 12 Demonstration Projects. These policies are based on the concepts of ‘area effects’ or ‘neighbourhood effects’ which suggests that the geographical proximity of disadvantaged households reduces their opportunity and increases disadvantage. Policymakers often use terms such as building ‘social cohesion’ or ‘social capital’ to promote the regeneration of housing estates through mixed tenure, without clearly defining these terms. This research takes a critical look at this theory by exploring the varying concepts surrounding the definition of social cohesion and the diverse mixed-tenured policies in the UK. Using leading literature on social cohesion and community engagement, it produces four themes for identifying social cohesion in mixed-tenure housing estates. The analysis is derived by studying the two demonstration projects of the Mixed Communities Initiative located in London.