Findings of an audit on the use of the MCA and Safeguarding Adults procedures across the nine prison and young offender institution healthcare teams in London. The audit reveals that: safeguarding is afforded a high priority by offender healthcare services; the organisational infrastructures for safeguarding (policies, procedures, training, etc) were rated higher than the infrastructures for the Mental Capacity Act (MCA); there are good working relationships between prison authorities and healthcare services around safeguarding, but the role of healthcare staff in safeguarding is limited by the prison context; mental capacity tends to be treated within offender healthcare services as an aspect of safeguarding; knowledge of and practice around the MCA is patchy – senior clinicians tend to have a good grasp of their obligations under the Act and how to apply them, while frontline nursing and other staff generally do not; there is a very weak infrastructure to support practice in relation to the MCA (policies and procedures, training, information, guidance, supervision, records); it is recommended that priority be given to strengthening the infrastructure to ensure that frontline practice in offender healthcare services is compliant with the MCA and the Care Act.