The UK criticality assessment of technology critical minerals and metals was commissioned by the Department for Business, Energy and Industrial Strategy (BEIS). 26 candidate materials were assessed for their potential criticality to the UK economy in terms of their global supply risk and the UK economic vulnerability to such a disruption. Eighteen of the these have a ‘high’ potential criticality rating based on these criteria, and constitute the UK Critical Minerals List 2021. Whilst this preliminary assessment has highlighted the potential UK criticality of many minerals, the reliability of the findings can be improved by refinement of the methodology and the underlying datasets. Owing to the dynamic and complex nature of mineral supply chains and inherent data shortcomings, it is inevitable that such criticality assessments may fail to identify potential problems. Given the continual evolution of global demand and supply patterns, certain minerals not included in this study will be considered for inclusion in future assessments. It is also important to stress that criticality assessment is based on existing data and understanding. It cannot, therefore, be used to predict future security of supply problems or trajectories of mineral demand.