This is an article about secondary schools in England, and what type of school is fair and efficient for a national education system. It discusses what "fair" could mean in this context, summarises some key policy revisions since 1944 in this light, and reminds readers of the damage caused by unfairness within education. Most notably it discusses the almost complete introduction of comprehensive schools by the 1970s, and the subsequent proliferation of new school types. The article then presents the methods used for the illustrations from secondary data that follow. Based on the Annual Schools Census 1989 to 2014, the article shows that the clustering of disadvantaged students using all available indicators has declined over historical time. This may be largely determined by an increase in prevalence created by immigration, sensitivity and improved diagnosis, and economic downturn. However, the system shows considerable variation between regions and areas linked to the local diversity of schools. Selective, faith-based, converter academies and free schools, as opposed to local authority comprehensives, are disproportionately in areas with the greatest segregation of disadvantaged students. And this occurs for no gain in improvement. The article concludes that the comprehensive ideal is not simply worth retaining, but that its implementation could be seen as the clear ethical duty of any secretary of state.