Inclusion Criteria:  All convicted male inmates over the age of 18 years old who indicate a history of interpersonal complex trauma will be invited to participate in this study. The ITQ will be used to identify the presence of complex trauma. It should be noted that potential participants may present with different clusters of PTSD and CPTSD symptoms; it is thought that this should not compromise the overall integrity of the study (Facer-Irwin et al, 2021). The selection process should also help to ensure:  An adequate level of mental and physical health and substance misuse stability so as to enable them to cope with the requirements of the intervention as determined by the local Multi-disciplinary Mental Health Team (MDMHT). Willing to participate for therapeutic and rehabilitative reasons and to have voluntarily given their written consent. Serving a sentence of 6-months or more and able to complete all follow up assessments prior to their liberation. Have a sufficient level of literacy skills that will enable them to engage with the course written material. Learning disabilities or difficulties will be considered on a case by case basis as discussed with the Treatment Manager. Located in a mainstream residential location.  Exclusion Criteria:  It is intended that as fewer prisoners as possible will be excluded from this study. Therefore, the following exclusion criteria are primarily based on ensuring the safety or the individual, other participants/staff and the good order and functioning of the prison establishment. This should include;  Prisoners who present as a high risk of institutional violence and requiring segregation from mainstream residential units Those who are on frequent observations for suicide and self-harm at any time in the week prior to the intervention starting. Enemies and those who have formed intimate relationships with each other whilst in custody will also be allocated to separate groups to ensure appropriate therapeutic dynamics. This will be undertaken in consultation with staff from establishment security department.