OBJECTIVES: To quantify geographical concentration of falciparum malaria cases in the UK at a hospital level. To assess potential delay-to-treatment associated with hub-and-spoke distribution of artesunate in severe cases. DESIGN: Observational study using national and hospital data. SETTING AND PARTICIPANTS: 3520 patients notified to the Malaria Reference Laboratory 2008-2010, 34 patients treated with intravenous artesunate from a tropical diseases centre 2002-2010. MAIN OUTCOME MEASURES: Geographical location of falciparum cases notified in the UK. Diagnosis-to-treatment times for intravenous artesunate. RESULTS: Eight centres accounted for 43.9% of the UK's total cases; notifications from 107 centres accounted for 10.2% of cases; 51.5% of hospitals seeing malaria notified 5 or fewer cases in 3 years. Centres that saw <10 cases/year treat 26.3% of malaria cases; 6.1% of cases are treated in hospitals seeing <2 cases/year. Concentration of falciparum malaria was highest in Greater London (1925, 54.7%), South East (515, 14.6%), East of England (402, 11.4%) and North West (192, 5.4%). The North East and Northern Ireland each notified 5 or fewer cases per year. Median diagnosis-to-treatment time was 1 h (range 0.5-5) for patients receiving artesunate in the specialist centre; 7.5 h (range 4-26) for patients receiving it in referring hospitals via the hub-and-spoke system (p=0.02); 25 h (range 9-45) for patients receiving it on transfer to the regional centre from a referring hospital (p=0.002). CONCLUSIONS: Most UK hospitals see few cases of falciparum malaria and geographical distances are significant. Over 25% of cases are seen in hospitals where malaria is rare, although 60% are seen in hospitals seeing over 50 cases over 3 years. A hub-and-spoke system minimises drug wastage and ensures availability in centres seeing most cases but is associated with treatment delays elsewhere. As with all observational studies, there are limitations, which are discussed.