The main data are vegetation composition percent covers in a series of experimental plots situated in the United Kingdom. These data were collected by others and have been rescued and synthesized for this resource. There is a unique ID identifying the plot from which vegetation data were recorded. These unique IDs are also used in the other .csv file, which provides the experimental design information for each plot in each experiment, together with information on further former N deposition experiments, where designs have been characterised but vegetation data are not available at this time. Data were collected over different years, ranging from 2000 to 2021, in experiments of different length and design and methods that have been translated into a common measurement scale. The supporting documentation provides further information on each of these experiments, and when and how vegetation data were collected and subsequently derived Full details about this dataset can be found at https://doi.org/10.5285/b9e76736-7db9-4576-acd9-dfdf9f8ff9a3