I'm looking for data about past floods in the UK. I know that the Environment Agency provides historic water level readings and also does predictions about possible floods at http://environment.data.gov.uk/flood-monitoring/archive, but is there any place where I can get access to actual occurrences of a flood?
You could have look at Dartmouth Flood Observatory website.
They provide 1985 to current (according to the website) flooding data worldwide. Data is available in textual formats like HTML (recent events only) or XML. There is only centroids of the floods available.
If you are looking for flood extents (outlines), there is a shapefile available as well. However, the shapefile is updated infrequently, according to the website.
I could not find data later than 2010 though.