Pupil Premium funding has been provided to schools in England since 2011, to reduce socio-economic segregation, and the attainment gap between disadvantaged pupils and their peers. There is little evidence it works. Some stakeholders are now considering whether funding should cease, or have a new objective. Evaluating the impact of such a funding policy is not easy because the relevant outcomes are sensitive to demographic, economic and other concurrent policy changes. These issues are addressed using the National Pupil Database, comparing the poverty gap in primary schools from 2006 to 2019, focusing on pupils who would have attracted Pupil Premium funding, if it existed, in any year and under any economic conditions. After 2010, the segregation of long-term disadvantaged pupils and their peers reduced in Years 1 and 6, and their attainment improved relative to their peers at ages 7 and 11. However, assessments changed after 2014 and this complicates the pattern. A regression model suggests that relative attainment for poor pupils improved markedly in the Pupil Premium era, even in regions like the North of England which have faced criticism for apparently "failing" their poor pupils. We argue for retaining the Pupil Premium policy.