ZURICH – Switzerland voted on Sunday on whether to back a proposal to cap the country’s population in a referendum likened to Britain’s Brexit vote, which could have far-reaching consequences for the economy and Bern’s relations with the European Union.

Driven by concern about immigration, pressure on public services and housing, the constitutional change pitched by the right wing Swiss People’s Party, ​or SVP, would mandate that the population must not exceed 10 million by 2050. Official projections put it on track to do ‌so by ‌the early 2040s.

The unprecedented scheme to dictate population levels by law sits alongside burgeoning efforts by the ​political right in Europe to set tougher curbs on immigration, fed by discontent about the cost of living, weak economic growth and crime.

“If it goes above 10 million, it will become tight, and immigration should be restricted,” said Helen Gulea, a 58-year-old seamstress and part-time ⁠kiosk worker in Zurich, originally from Kenya, who voted by post for the cap.

Results of the vote are expected to begin coming in from around midday.

If the proposal were adopted, reaching the 10 million mark would trigger a process that could make Switzerland scrap its free movement of labor agreement with the EU, whose member states supply much of the Alpine country’s workforce.

Switzerland’s aging ​population is already above 9 million and polls suggest ⁠public opinion is finely balanced.

A final survey this month showed opinion turning against the proposal. An earlier poll had suggested it could pass.

Patrick Leisibach, a migration expert at think tank Avenir Suisse, said concern ⁠was now widespread that overcrowding ​was stretching public infrastructure to the limit.

“There’s a traditional anti-immigration vote on the right wing, but ​these days even many on the left are feeling the pressure,” he said.

Under its system of ​direct democracy, the ‌Swiss electorate generally votes four times a year on national referendums, which also require the support of the majority of its cantons to pass.

The government and parliament have urged voters to reject the SVP’s so-called sustainability initiative as folly at a delicate time for Switzerland’s export-oriented economy.

Johanna Alves, a 33-year-old Swiss student, voted against it, saying she worked in an international environment which, she worried, ‌could be in jeopardy if the proposal passes.

“And I think it will also be really terrible for the Swiss economy in general, for our health care system, for research, for all of it,” she said.

Last year, President Donald Trump slapped the highest U.S. tariffs in Europe on Swiss goods and the prospect of a population curb could complicate corporate planning.

But SVP lawmaker Thomas Matter argued Swiss gains in prosperity had not kept pace with overall…