Within England there has been a growing recognition of the need to increase students’ attainment in science especially amongst disadvantaged students whose schools receive additional state funding to support their education. There is, in England, currently no paired mentoring programme in which undergraduates, studying STEM subjects, are paired up with disadvantaged students (aged between 15-16) while they are studying towards their science GCSEs (public examinations). This peer-mentoring project in which students, from socio-economically disadvantaged backgrounds, are paired with undergraduate students was designed and implemented in order to help improve both their academic achievement in science and their attitudes towards studying science and related subjects in the post compulsory phase of their education up to, and including, university level. The project is a comparative study involving a control (n=42) and intervention (n=42) group from across four state secondary schools in England. Unlike previous evaluations of mentoring projects, that relied solely upon participants’ (mentors, mentees and programme coordinators) self-evaluations, this study uses student school test and public examination data as a measure of academic achievement in addition to questionnaires to investigate their attitudes towards science. This paper reports on the way that this project was designed, issues arising in its implementation, as well as preliminary results regarding its effectiveness.