Little Englander
The Little Englanders were a British political movement who opposed empire-building and advocated complete independence for Britain's existing colonies. The ideas of Little Englandism first began to gain popularity in the late 18th century after the loss of the American colonies, but later came to be strongly associated as a reference to members of the Liberal Party who opposed further expansion of the British Empire. The term "Little Englander" itself was first recorded in 1833, and was usually derogatory.
Since the 2010s, especially after the 2016 Brexit referendum, the term has become a popular derogatory epithet for an English chauvinist who mistrusts the European Union, international cooperation, and foreigners in general. "Gammon" has been used similarly in British political culture since 2012.