The author describes the experience of undertaking psychotherapy with highly defended patients in the context of a prison cell in a London prison, rather than her customary private practice. She presents an ethical challenge to psychotherapists to enhance the quality of their private work by stepping outside the familiarity of the consulting room into contexts which involve change, challenge and subsequent clinical development. The author highlights theories around violence and the sexualization of aggression and describes the demand of ‘in the moment’ ethical challenges present in work with two patients, one convicted for child abuse and the other for rape. The paper also raises questions around how the aggression inherent in the prison system leads to the perpetuation of offending, and how psychotherapy allowed the patients to begin to work through their histories enveloped in their offences.