The National Health Service (NHS) is the umbrella term for the publicly funded healthcare systems of the United Kingdom, comprising the NHS in England, NHS Scotland and NHS Wales. Health and Social Care in Northern Ireland was created separately and is often locally referred to as "the NHS". The original three systems were established in 1948 as part of major social reforms following the Second World War. The founding principles were that services should be comprehensive, universal and free at the point of delivery—a health service based on clinical need, not ability to pay. Each service provides a comprehensive range of health services, provided without charge for people ordinarily resident in the United Kingdom apart from dental treatment and optical care. In England, NHS patients have to pay prescription charges; some, such as those aged over 60, or those on certain state benefits, are exempt.

The National Health Service (NHS) is the publicly funded healthcare system in England, and one of the four National Health Service systems in the United Kingdom. It is the second largest single-payer healthcare system in the world after the Brazilian Sistema Único de Saúde. Primarily funded by the government from general taxation, and overseen by the Department of Health and Social Care, the NHS provides healthcare to all legal English residents and residents from other regions of the UK, with most services free at the point of use for most people. The NHS also conducts research through the National Institute for Health and Care Research (NIHR).