Guernsey is under the responsibility of the United Kingdom but they dont count as a part of the U.K, as well as the European Union. Guernsey is located in the English Channel on the coast of Normandy. They have complete autonomy over internal affairs, and they are discussing total independence from the British Crown.
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Guernsey is one of the UK's three "crown dependencies", along with Jersey and the Isle of Man.
"Jersey and Guernsey have their own legal and healthcare systems as well as their own separate immigration policies with 'local status' in one bailiwick having no jurisdiction in the other. They exercise bilateral double taxation treaties. Since 1961 the bailiwicks have had separate courts of appeal, but generally the bailiff of each bailiwick has been appointed to serve on the panel of appellate judges for the other bailiwick."