This article details the impact arising from a sustained public-engagement activity with sixth-form students (16- to 17-year-olds) across two further education colleges during 2012/13. Measuring the impact of public engagement is notoriously difficult. As such, the engagement programme followed closely the recommendations of the National Co-ordinating Centre for Public Engagement (NCCPE) and their guidance for assessing Research Excellence Framework 2014 (REF2014) impact arising from public engagement with research. The programme resulted in multiple impacts as defined by REF2014 under 'Impacts on society, culture and creativity'. Specifically: the beneficiaries' interest in science was stimulated; the beneficiaries' engagement in science was improved; their sciencerelated education was enhanced; the outreach programme made the participants excited about the science topics covered; the beneficiaries' awareness and understanding was improved by engaging them with the research; there was tentative evidence of an improvement in AS-level grades; there was indirect evidence of an improvement in student retention. These impacts were evidenced by the user feedback from the sixth-form students collected from 50 questionnaires (split 16 and 34 across the two further education colleges), as well as testimonies from both the teachers and individual participants. This article will be of interest to anyone looking at how to evidence that public engagement has produced impact, in particular with regards to impact arising from a sustained public-engagement activity.