This paper reports the findings of an Economic and Social Research Council-funded study investigating patterns of participation in UK higher education science programmes across two decades. Using data on applications and acceptances to university, the paper describes trends in the proportions of candidates who choose to study science and science-related degree programmes. Two key findings emerge. Firstly, in terms of age, occupational background and ethnic group, patterns of participation in science subjects have remained relatively stable over the period considered. Where inequalities do exist they appear largely unaffected by policies aimed at widening access. Secondly, the characteristics of students who study the broad range of science and science-related subjects are little different to those of the wider student population. However, where differences do occur they are in the type of science degree that individuals choose, with entrants from traditional backgrounds more likely to study the more prestigious science subjects. This is exemplified in the physical sciences which remain largely the preserve of White, traditional-age students from professional and managerial backgrounds. The analyses suggest that policies aimed at increasing or widening participation in science in UK higher education appear to have had limited impact on the social composition of the full-time undergraduate science population, in terms of their age, occupational and ethnic group. (Contains 3 notes, 5 tables and 7 figures.)