In 2001, the United Kingdom experienced its worst epidemic of foot-and-mouth disease (FMD). To date approximately 3.9 million animals have been culled and direct and indirect revenue losses are probably in excess of pound 12 billion. This study was carried out to investigate the biological characteristics of the FMD virus strain O/UKG/2001 responsible for the epidemic. Animal transmission experiments indicated that this strain is not host restricted and will infect the three main susceptible livestock species (cattle, sheep and pigs). Immunisation with high potency emergency vaccine derived from O(1) Manisa strain of FMD virus protected all three species against clinical disease when challenged with FMD virus strain O/UKG/2001.