Adapting risk assessments to a changing terrorism landscape: Revising the extremism risk guidance

Abstract The Extremism Risk Guidance‐Revised (ERG‐R) updates and expands the ERG22+ framework, which has guided terrorism risk assessment in prison and probation across England and Wales since 2011. Developed by His Majesty's Prison and Probation Service (HMPPS) Counter Terrorism‐Assessment and Rehabilitation Centre (CT‐ARC), the ERG‐R responds to key shifts in the terrorism landscape, including the growth of online radicalization, greater involvement of younger individuals, an increase in extreme right‐wing convictions, and more fluid ideological affiliations. The revised framework comprises 36 factors, building on the original three dimensions (engagement, intent, and capability) by adding a fourth dimension addressing protective and risk‐mitigating factors, enhancing alignment with Structured Professional Judgment (SPJ) methodology. Its development drew on a comprehensive literature review, consultation with the Correctional Services Advice and Accreditation Panel (CSAAP), external peer review, and a 12‐month pilot across custodial and community settings. The ERG‐R enhances operational guidance for assessing dynamic risk, including tracking change over time and informing case prioritization, replacing fixed risk levels with more nuanced case management. Following practitioner training, the ERG‐R was formally implemented across HMPPS in March 2025. This technical report outlines its theoretical foundations, development process, and practical application and considers its adaptability to jurisdictions beyond England and Wales.