The expansion of higher education (HE) in the UK has disproportionately benefited young people from relatively rich families: the gap between rich and poor in terms of participation in HE having widened since the 1970s. We explore a neglected possible cause of this class difference: that the labour market fails to provide sufficient incentives for potential entrants from less advantaged backgrounds to enter HE. Most studies of the rewards from participating in HE in the UK suggest that the rates of returns are sufficiently high to provide clear economic incentives to participate. However, until recently, most studies generated estimates of the average rate of return to graduation, which could overestimate returns to marginal entrants, particularly those from disadvantaged backgrounds. In this review we examine the methodological problems faced by more targeted studies of the rates of return to graduation and review their key findings concerning the economic returns to non-traditional entrants.