Aim The aims of this study were to identify all people with Lesch–Nyhan disease (LND) born in the UK between 1988 and 2008, and to obtain a clinical profile including age at diagnosis, genetic background, family history, neurological signs, and medications. Method Potential participants were contacted through the British Paediatric Neurology Surveillance Unit. Questionnaires were sent to each child’s paediatric neurologist or primary consultant. Two purine laboratories provided metabolic information. Results Twenty-three live males with LND in the 0- to 20-year age band and eight live males over the age of 20 years were identified. Thirty-one live people with LND were identified in the UK in 2008, giving a prevalence of 1 in 2 million people. Over the 20 years of study, there was a mean incidence rate of 0.18 per 100 000 live births, range 0 to 0.5. Interpretation To our knowledge, this study is the first to provide details of the prevalence and incidence of LND in the UK. The data highlight that clinical profiles, at the time of diagnosis, and management of the disease are variable. There is the need for ongoing monitoring of allopurinol dosage and metabolic screening.