Purpose The use of mental health treatment requirements (MHTRs) has not proven to be successful at meeting the mental health needs of the probation population in the UK, largely through underuse of the requirement or lack of available services. The paper aims to discuss this issue. Design/methodology/approach This paper investigates a method of meeting those needs without the use of MHTRs by embedding third sector services within the probation environment. Findings Results indicate a significant impact after a six-month follow-up in symptomology across measures of depression, anxiety, general distress and social functioning; also indicated is a significant result on recidivism, with 74 per cent of participants committing no further offences in the 12 months following treatment. Originality/value These results represent the only evaluation of embedded, third sector mental health services in a probation environment in the UK, and highlight a further need to embed specialist mental health services within the probation environment and generalise that practice to other forms of service structure and therapeutic methodology.