The paper makes use of newly linked administrative education data from England to understand better the determinants of participation in higher education (HE) among individuals from low socio-economic backgrounds. The data are unique in being able to follow the population of two cohorts of pupils in England -those who might have entered HE between 2004- 2005 and 2006- 2007- from age 11 to age 20 years. The findings suggest that, although large differences in HE participation rates and participation rates at high status universities by socio-economic background remain, these differences are substantially reduced once prior achievement is included. Moreover, these findings hold for both state and private school pupils. This result suggests that poor achievement in secondary schools is more important in explaining lower HE participation rates among pupils from low socio-economic backgrounds than barriers arising at the point of entry to HE. These findings are consistent with the need for earlier policy intervention to raise HE participation rates among pupils from low socio-economic backgrounds.