This dataset consists of plant species presence and abundance in different sizes and types of plots from 256 1km x 1km square sites surveyed across Great Britain in 1978. Many of the plots were repeated in 1990, 1998 and 2007. General information about the plot was recorded including plot number and type as well as species presence and (usually) cover. Data were collected under the Countryside Survey long term monitoring project managed by the Centre for Ecology & Hydrology.