One of the defining characteristics of countries, such as the United Kingdom, with low social mobility are stark, persistent gaps in the school results between children from deprived backgrounds and their more advantaged counterparts. Far from acting as the great social leveler, education systems can perpetuate inequalities, and enable the privileged in society to consolidate their already substantial advantages for future generations. Sutton Trust's central concern is with those children on the wrong side of the educational divide; the price of unfulfilled potential is a lifetime of missed opportunity--a loss not only for the individual but the country as a whole. A recent analysis argues that attainment gaps between the most and least deprived schools have been narrowing slightly in recent years, but gaps between pupils within schools remain stark. This report asks the question: What is the achievement of a pupil in a highly deprived school compared with a similar child in a less deprived school? The findings in this report are unequivocal, and make for uncomfortable reading for parents and policy makers alike. Whether expressed in terms of "raw" gaps--in which the individual characteristics of pupils are ignored--or conditional gaps--which take account of the social background, ethnicity, and prior attainment of pupils--the attainment of otherwise similar pupils in deprived schools lags significantly behind those in the more advantaged schools. This is as much the case for pupils from deprived backgrounds as it is for the most highly academically able pupils. What is more, the research finds that those highly able pupils were more likely to have taken a vocational qualification at age 16 at the most deprived schools than highly able pupils at the least deprived schools. The report also reveals that there exists a "hidden poor" among pupils in schools who have at some point in their schooling been eligible for a Free School Meal, but who are not eligible for a Free School Meal in their current year. The Trust believes that all pupils who have been eligible for Free School Meals at some point in their secondary schooling should be recognized in the official measures of attainment gaps, and the premiums awarded to the most deprived schools. The Trust advocates the greater use of area wide banding, in which pupils of a range of abilities are enrolled at all local schools, as well as the use of random allocation (alongside other criteria) for admissions to over-subscribed schools. It is absolutely critical that pupils and parents receive sufficient objective information and guidance, especially at disadvantaged schools.