Racial trauma remains under-assessed in UK mental health practice, particularly among Black British individuals facing systemic, interpersonal, and historical racism. Standard diagnostic tools—such as the PCL-5, DASS-21, and ACE Questionnaire—fail to recognise racism as a distinct trauma source. U.S.-centric instruments like the RBTSSS and UnRESTS offer targeted assessments but lack cultural relevance in British contexts. This study introduces the Black British Racial Trauma Questionnaire (BBRTQ), a 60-item instrument designed to assess racialised distress within UK-specific institutional and historical frameworks. Forty-five Black British adults (aged 18–55) completed the BBRTQ online. Items were rated on a 5-point Likert scale, developed through qualitative interviews and expert review. Grounded in Helms’ racial identity theory, DeGruy’s post-traumatic slave syndrome, and Fricker’s epistemic injustice framework, exploratory factor analysis revealed a six-factor structure: Emotional Impact, Identity Conflict, Intergenerational Transmission, Systemic Exclusion, Resilience, and Survival Stress. These accounted for 71.2% of variance, with subscale reliability ranging from α = .84 to .91. Scoring yields a Total Trauma Index (TTI) and a Resilience Score, interpreted independently to distinguish trauma burden from culturally grounded coping. Their negative correlation (r = –.42, p < .001) supports the BBRTQ’s non-pathologising design. The BBRTQ demonstrates strong cultural specificity and psychometric robustness, supporting trauma-informed care and systemic reform in UK mental health services