Own work, map compiled from a variety of sources:
http://www.english-heritage.org.uk/publications/suffolk-rczas-national-mapping-programme-report/nmpfinal02-02-05.pdf (Suffolk coast prior to reclamation)
http://www.earthtools.org (Flegg and the Great Estuary)
http://www.antiquemaps.com/uk/mzoom/29159.htm (Fens, pre-drainage)
File:EastAnglia.png (elevation above 50m and 100m)

http://www.openstreetmap.org/ (coastline)
Transferred from en.wikipedia to Commons.
Amitchell125 at English Wikipedia