Vegetation species and soil data from a large national survey of calcareous grasslands, carried out in Great Britain in 1990-1993 (referred to as 1990) and 2006-2009 (referred to as 2007). Up to 128 12x12m plots were surveyed from across the country, selected on the basis of being representative of the calcareous grassland type. Details about plant species and soils were collected using standardized survey methods. The 1990 survey was completed under a contract from the Department of the Environment, by Lancaster University. The repeat survey in 2007 was completed under a NERC Grant by staff from Lancaster University, York University, Radboud University, Countryside Commission for Wales, National Museum Wales and the Centre for Ecology & Hydrology.