The unexpected appearance of fatal encephalitis in six elderly people living in New York in 1999, heralded the re-birth of arbovirology in the United States of America. The subsequent rapid spread through North America and impact of the disease on humans, birds, horses and a wide range of other species including alligators and frogs, has brought West Nile virus (WNV) to the attention of governments and the media, worldwide. The response of the public in the United Kingdom has not been hysterical, despite being fuelled by press reports that scientists have demonstrated the presence of WNV antibodies in birds in the UK. Nevertheless, concern has been expressed by government bodies either directly or indirectly connected with the potential health problems that could arise if WNV was introduced and caused the same degree of morbidity and mortality as that seen in the USA. Is the concern justified and are we likely to see significant health problems associated with WNV if this virus is confirmed to be present and circulating amongst birds in the UK? In this review I shall try to put the virus in its true context and assess the risks that WNV might pose both to animals and humans in the United Kingdom.