In this thesis, the patterns of population change in the British badger (Me/es me/es) population over a nine year period are presented. The results of a stratified, random survey undertaken between October 1994 and January 1997 were compared with those from an identical, baseline survey which was carried out between November 1985 and early 1988. l-km squares were the unit of survey: 22711-km squares were surveyed twice - once in the 1980s survey and again in the 1990s. The Institute ofTerrestrial Ecology's Land Classification Scheme was incorporated into the survey design to ensure that Britain's landscape types were evenly represented in the sample, and to facilitate reliable extrapolation to the whole country. There were estimated to be 50,241±4327 badger social groups in Britain in the 1990s, an increase of24% from the original survey. Average group size also increased. An estimate of relative abundance, based on a field sign index which was quantified for each sample l-km square, revealed that there had been an increase in badger numbers of75% between the surveys. Variables relating to habitat availability and persecution levels were recorded in both surveys. Changes in badger abundance were analysed with respect to changes in these variables between the two surveys. A decline in levels of persecution correlated with the increase in badger numbers. Tightening ofthe badger protection laws is believed to have brought this about. The relationships between badger group size, sett size and activity, and latrine use were investigated to further refine the survey results, and to provide a means to estimate badger numbers at a local scale. Social group size was found to be related to the number of active holes at the main sett. A predictive model was produced incorporating main sett active holes and latrine use within territories