In common with many other higher tariff universities in the United Kingdom, Durham University uses contextual data about the socio-economic circumstances of applicants to inform decisions about whom to admit to its undergraduate degree programmes. This paper draws on data for undergraduates who entered Durham University in the period 2018-2020 (N = 11,392) to assess the extent to which contextual offer making has been successful in widening participation and to examine how contextually admitted students (around a fifth of all entrants) have fared academically at the university in both relative and absolute terms. Analysis of this data shows that contextual offers have helped to increase the socio-economic diversity of the undergraduate population at the university with respect to POLAR quintile and other postcode-based measures of disadvantage, but not with respect to school type. Importantly, without the availability of contextual offers, a significant minority of contextually admitted students may not have received an initial offer of a place, and around half may not have had their offer confirmed after key stage 5 examination results were announced. Relative to standard offer entrants, contextually admitted students had slightly lower pass rates and slightly lower average marks in years 1, 2 and 3 of their degree programmes, and were substantially less likely to graduate with a first and slightly less likely to graduate with at least a 2:i. In absolute terms, however, contextually admitted students performed well at the university, with pass rates of 90% or more and average marks of 60 or higher across all 3 years of study, and rates of leaving with at least an upper second-class degree of more than 80%. Overall, contextual offer making at Durham University has been a success, helping to widen participation without compromising student success in absolute terms. Improvements to student support systems are needed, however, to help close the gap in relative rates of success at degree level.