England makes up about 85 percent of Britain’s population, and so dominates. But the English identity, while subsumed into the British one, is not entirely the same, drawing as it does on its own rich history and deeply embedded political and cultural traditions. In particular, the English are considerably less willing than their fellow Britons in Scotland and Northern Ireland to see themselves as a subset of Europe — there is more nativism and more “Little England” nationalism, which can veer into xenophobia.

Robert Tombs, a professor at St. John’s College, Cambridge, and the author of “The English and Their History,” said he saw the emergence of something deeper in what has become a debate fueled more by emotion than fact.

“The campaign seems hardly about Europe at all, but it’s all about us and the English identity,” Professor Tombs said. “There is a deep-seated sense that we the people ought to make decisions and not be led by an elite and not be told what to do by foreigners, even by the ones we like, like Obama, and there is a stubborn resistance to parades of international institutions telling us how to vote.”