Alderney concentration camps
Guernsey
The Alderney camps were camps built and operated by Nazi Germany on the island of Alderney during its World War II occupation of the Channel Islands. Alderney had four forced/slave labour sites, including Lager Sylt, the only Nazi concentration camp on British soil during the wartime occupation.
Prison data from Wikidata (CC0). Summary from Wikipedia (CC BY-SA).