Their nationalism is proving to be a key part of the exit debate. It embodies national pride, nostalgia and a sense that something precious to these islands is being destroyed by the many European Union citizens who, allowed by the bloc’s rules to move to any member nation without a visa, have come to Britain to live and work, attracted by a vibrant economy and jobs.

“People here are self-reliant and very hardheaded, and they have sacrificed for our independence and want to retain it,” said Bob Spink, a former Conservative member of Parliament from Essex who was an early supporter of a British exit. He compared Essex, which is often the butt of “dumb blonde” jokes in the rest of Britain, to Texas.

The first legislator to defect to the anti-immigration, anti-Europe U.K. Independence Party, or UKIP, back in 2007, Mr. Spink quit the Tories because he wanted a referendum on leaving the European Union. While he lost his seat in 2010 to Rebecca Harris, a Conservative, he still speaks for many here.

“People want to vote for the people who make our laws and set our taxes; they want to talk to them and be able to throw them out; and they don’t want to give up sovereignty, independence and democracy to Brussels at any price,” he said.

English nationalism is growing, and it is being encouraged by the referendum. This United Kingdom of four nations may be split in the end, with England and Wales voting narrowly to leave and Scotland and Northern Ireland voting heavily to remain. That could create further calls for pushing more governmental power to the local and regional levels, Scottish independence or the creation of a separate English parliament, as Scotland, Wales and Northern Ireland already have.

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.”

Every nation has its myths, Professor Tombs said. “But myths are important, and the notion that the people decide — Magna Carta and the Reform Act — mean that those who rule us have to do what we say.”

Ms. Harris, the current member of Parliament here, supports leaving the European Union, a position that puts her at odds with Prime Minister David Cameron, a fellow Conservative, who is leading the campaign to stay in the bloc. “People can sense that politicians are not in control anymore, that they can’t deliver, and people have a very strong feeling that they’re no longer in control of their politicians,” she said.

The working class feels that it is slipping behind, people here said, and construction jobs that used to be theirs in London are now going to skilled European immigrants who work more cheaply. “People say to me that ‘we have to control the numbers to protect what we have,’ ” Ms. Harris said. “They say, ‘We’re a tiny nation and we’re full, Rebecca, we’re full.’ And there’s anger that Europe wouldn’t let us agree to have more control over who comes, that there’s a loss of control.”

David Manclark, 58, who attended the Brexit debate in South Benfleet, said that “a lot of people feel exiled in their own country.” Around here, he said, “we feel we need to be able to control our own borders and bring in the people we need.”

Robert Baron, 67, said: “It’s being British. It’s knowing that other people can’t understand our way of life as well as you can living in your own country.”

Colin MacLean, 45, a local council member who helped organize the debate, was one of the few to speak out in favor of Britain remaining part of Europe. He runs a real estate agency with 30 employees. “Think of the shock Brexit would create,” he said. “Mortgage rates would rise and prices drop, and all the good work of the last few years would go to waste.”

Though he said he felt British and “not particularly European,” Mr. MacLean added: “But I like the privileges E.U. membership brings. And I don’t see problems at the borders — I see people there.”

Tom Tugendhat, a former British Army officer and new Conservative legislator from Kent, said Englishness was more an attitude than a political stance, a confused emotion wrapped up in identity. “ ‘We few, we happy few, we band of brothers’ — there’s a bit of Henry V in all of us,” he said.

“But we forget that Shakespeare emerged from the tradition of courtly love that emerged from the Continent and perhaps the Arab world,” he said, “and that Magna Carta was a Latin document immediately translated into the vernacular, which was French, and signed by a French king under pressure from mostly French barons who didn’t include most people, who were Anglo-Saxon.”

At the same time, Mr. Tugendhat said, globalization has prompted questions among the English like: “Who are we, and are we less of ourselves than we used to be?”

Clare Foges, a former speechwriter for Mr. Cameron, described the Conservative dilemma this way: “There is the strong element in the Tory character that is sensible, utilitarian, financially pragmatic, and there is the part that thinks to the strains of Elgar and stirs at the words ‘destiny,’ ‘democracy’ and ‘nation.’ ”

That’s the dilemma of England, too: How much economic damage are voters willing to risk for the ability to feel fully sovereign and in control of immigration?

Essex clearly wants out, and so do the most recent legislators, Mr. Spink and Ms. Harris. But both think that despite the tide of opinion in Essex, Mr. Cameron and other proponents of staying in Europe will eke out a victory. Ms. Harris laughed and said, “Cameron always wins.”

Until, of course, he doesn’t.