Campaigners hold signs supporting the “remain” group that seeks to avoid a Brexit, ahead of Thursday’s European Union referendum. (Justin Tallis/AFP/Getty Images)

The story of London’s East End is the story of migration: five centuries of minority communities living in tandem — and sometimes tension — on the periphery of the British capital.

Palatine Germans followed French Huguenots; Bangladeshi Muslims followed Eastern European Jews. Each community has left its traces here: the curry houses, the all-night bagel shops, and, in warm weather, the lingering scent of coriander.

On Thursday, after months of a heated and largely anti-immigrant campaign, voters will decide whether Britain should remain in the European Union. But in the East End and across London, many have begun to wonder whether the Brexit vote could spell the end of their city: multiethnic, international and cosmopolitan.

For the writer Rachel Liechtenstein, who has published two books on the history of the East End, the vote represents an affront to the idea behind the community that welcomed her grandparents, Jewish refugees from Poland who met in English classes on Brick Lane in the 1930s.

For Ansar Ahmed Ullah, a Bengali Muslim and community activist in his mid-50s who has lived in the East End since the 1980s, Brexit, which he strongly opposes, is less a political decision than a matter of what he called “emotional loyalties.”

Ullah was standing outside the Brick Lane Mosque, an unassuming Georgian edifice at the corner of Brick Lane and Fournier Street that was once a synagogue and, before that, three different churches. Some call it the only house of worship outside Jerusalem to have been used by all three of the largest monotheistic faiths.

An elaborate steel minaret abuts a facade still decorated with the sundial that French Protestants installed in the 18th century. Inside, mosque leaders have painstakingly maintained Hebrew plaques commemorating the Jewish teachers who taught at the synagogue’s school in the early 20th century.

“The mosque is a witness to the different migrating groups,” Ullah said. “Different groups coming to the East End, settling, and making it their home.”

If today much of East London is heavily gentrified — dotted with the kind of boutiques that sell only Austrian wines and restaurants that feature Damien Hirst installations — the area was for centuries the first stop for immigrants after they arrived in Britain.

“The idea that somehow we’re going to disconnect ourselves from the rest of Europe and the rest of the world . . . it’s horrifying to me, really,” Liechtenstein said. “We are such a multicultural society in London, and that’s the joy of being in the city.”

In recent years, London’s distinct brand of multiculturalism has been facilitated by E.U. laws that require the British government to accept migrants from other countries in the 28-state bloc.

There are approximately 3.3 million E.U. nationals living in Britain, an increase of about 2 million since 2003. About 2.1 million of them hold jobs in Britain.

Should a majority of voters support the “leave” campaign, it is not clear what will become of the European citizens living and working here, or what their legal status will be.

While many of these E.U. citizens have come from Greece, Italy, Spain and Portugal in the wake of the euro-zone economic crisis, the overwhelming majority is Eastern European, from former communist-bloc countries that joined the European Union in 2004.

When other member states imposed “transition periods,” limiting immigration, Britain, then under the leadership of Tony Blair, encouraged Eastern European emigration, largely to promote economic growth.

The largest foreign national community in Britain is Polish. According to an online poll conducted this week by the Warsaw-based Institute of Market and Social Research, “fear” and “uncertainty” are the predominant emotions Polish citizens in Britain associate with Brexit.

Of those surveyed, 79.4 percent support “remain.”

Jakub Krupa, a journalist and activist for Britain’s Polish community, said that the primary concern is that the British government has not specified what will happen in the wake of a vote to leave the union.

“We can expect administration procedures that will be hellish to go through,” he said. “There was the expectation that this would be clarified as soon as possible. But no one really explained what would happen. No one really even knows that.”

Compared with other immigrant communities, he said, Poles have “literally no political representation.” The only member of Parliament of Polish origin is Daniel Kawczynski, a Warsaw-born conservative who supports the “leave” campaign.

“Poles have no one who can speak on their behalf,” Krupa said. “And with Brexit, who will represent the community after that?”

A growing number of Polish citizens who have lived in Britain for longer than the five required years are applying for British citizenship, which would shield them from any status changes, he said.

In the immigrant communities of the East End, there are those who support Brexit, generally on the grounds that limited housing and social services should be reserved for struggling British citizens.

But the idea that a single vote could send certain communities away presents an image of a Britain that, for many, is unrecognizable.

In the final days before the vote, the neighborhood assembled for the Immigrants of Spitalfields Festival, a three-day affair that featured demonstrations on properly wearing a sari and lectures on the literature of the Jewish East End.

Liechtenstein was volunteering at the Sandys Row Synagogue, London’s oldest Ashkenazic synagogue, which was once a Huguenot chapel.

“My own grandparents came as immigrants,” she said. “Had it been closed, well . . . we wouldn’t be here celebrating.”

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