The British Paediatric Surveillance Unit (BPSU) is a national system in the United Kingdom that monitors rare childhood diseases and conditions. Established in 1986, it collects data from pediatricians across the country to improve understanding and treatment of these conditions. The information gathered helps inform public health policies and clinical practices. BPSU operates through a network of pediatricians who report cases of specific conditions each month. This surveillance system plays a crucial role in identifying trends, assessing the impact of interventions, and supporting research efforts related to child health. It contributes significantly to the field of pediatric medicine and public health.