The definition of Europe is not a fixed historical constant. Including various islands in particular continents is an essentially arbitrary choice.
Europe as a geographic feature is a distinct concept from Europe as a sociopolitical entity. It is clear that Europe and the UK have been diverging culturally, socially, and politically for some time now.
UK does not have the political connections, open borders, collectivization of resources, harmonized regulations, shared currency, or really any other connection to the rest of the Europeans beyond memory.
