Using Mentalization Based Therapy to Support Children and Adolescents Referred to Specialist Mental Health Services in the NHS for Aggressive and/or Violent Behaviour

Inclusion Criteria: * Age 10-17 years at the time of referral; * Aggression and/or violence are indicated at referral or assessment; * Participation in the evaluation would not interfere with statutory orders; * Child and parent/carer (for children 10-15 years) are able to consent and engage with the study materials; * Living in the community at time of referral and no imminent plans to move to hospital, residential, or secure settings. Additional inclusion criteria for participants recruited from a clinician's existing caseload: * There has been no direct contact between child and FCAMHS clinicians, including assessments. * There has been no indirect therapeutic support provided by FCAMHS e.g. advising non-FCAMHS professionals on therapeutic support. * It is permissible for the clinician to have previously engaged in consultation activities where these did not involve contact with the child. Exclusion Criteria: * Age under 10 or age 18 or older at the time of referral; * No evidence of aggression and/or violence indicated at referral or assessment; * FCAMHS are only offering a one-off consultation or assessment (e.g., the network around the child requires support to manage risk but additional input is not required); * Child's level of English is not sufficient to engage in the intervention; * Child and/or parents/carers refuse to engage with FCAMHS; * No statutory service is involved in supporting the child; * No statutory service will agree to hold the child's case open for a minimum of six months. * Currently involved in another psychological intervention research study.