The data are projected extreme sea levels at approximately 2 km spacing around the UK coastline, including England, Wales, Scotland, Northern Ireland, and Isle of Man. The data were produced by the Met Office, using estimates of present-day extreme sea levels at all open-coast Coastal Flood Boundary point locations, provided by the Environment Agency and projections of 21st Century time-mean sea level change prepared at the Met Office.

Projected extreme sea level values are described for 16 different annual probabilities of exceedance (return levels), ranging from 1:1 to 1:10,000, identified in the shapefile as ‘t1’ to ‘t10000’. Confidence levels relating to the 5% and 95% lower and upper bounds of confidence are included, identified in the shapefile with the prefix ‘c1_’ and ‘c3_’ respectively, as well as the 70% confidence level identified in the shapefile with the prefix ‘c2_’.

The data were produced to put the projected future mean sea level change in the context of the present-day extremes. The data were produced by combining the best estimates of present-day extreme sea levels with projections of mean sea level change. The data covers the period from 2020 to 2100 and is available for each decade (i.e., 2020, 2030... 2100).