Conventionally, the use of imprisonment is justified partly by its supposed reformative potential (McNeill and Schinkel 2016), and rates of reoffending among life- and long-sentenced prisoners are relatively low (Ministry of Justice 2017). Yet criminological research has not generally considered the identity changes which occur among long-term prisoners during their sentences as potential evidence of desistance. Instead, research on desistance from crime has generally focused on what happens after a sentence of imprisonment, which is itself, implicitly, a purely punitive and negative experience. The sociology of imprisonment does not support such a flat, untextured view. It suggests that long-term prisoners often lose and then rediscover a sense of agency and identity (Crewe, Hulley and Wright 2016), change in their orientation towards their offences (ibid; Ievins 2017), and undertake a range of ethical practices whose private and public meanings can signal reformed selfhood (Williams 2017). Because the moral and social environment of a prison is so dissimilar to the outside world, it is hard to describe these practices confidently as ‘desistance’, despite the obvious resemblances and the changes in behaviour which sometimes go with them. This project aims to integrate these two research perspectives, to ask how prisoners’ moral beliefs and ethical practices are shaped by the prison’s underlying ‘moral economy’, and whether these adaptations constitute desistance.