The United Kingdom is holding a referendum on Thursday June 23 to decide whether the country should leave or remain in the European Union. The heated debate has led to market uncertainty, and even the suspension of both the “Leave” and “Remain” campaigns after the killing of Labour MP Jo Cox on Thursday.

Here’s an explainer on the Brexit debate’s key issues, players and how Britain’s potential exit from the EU could affect Canada.

WHAT ARE THE KEY ISSUES?

• Fighting for sovereignty: The “Leave” camp believes Britain is held back by the EU, hampered by rules and laws that have been imposed on the country and receiving little in return for the billions it spends on membership costs.

• The immigration divide: Brexit supporters argue that the U.K. should have better control of who enters the country, and even reduce the number of people going there to live and/or work. One of the key pillars of the EU is the free movement of labour, meaning any citizen from the other 27 countries has an automatic right to live there.

However, the “Remain” camp argues that the flow of young immigrants to Britain drives economic growth and contributes to paying for public services.

• Trade and the economy: Those who want Britain to stay argue that its membership makes it easier to sell goods and services to the 500 million consumers who are part of the EU. While 44 per cent of Britain’s exports go to the EU and eight per cent of EU exports go to Britain, “Remain” supporters say that the country would lack negotiating power if the country quit the bloc.

“Leave” supporters argue that Britain could better diversify international trade links if it leaves the EU. They argue the U.K. would be able to ink deals with nations more quickly, since 28 different member countries’ differing priorities wouldn’t have to be considered.

WHO ARE THE MAIN PLAYERS?

U.K. Prime Minister David Cameron

Once skeptical of the European Union, the Conservative leader pledged in 2013 to hold reform negotiations with the bloc and to hold a referendum regarding Britain’s membership. Cameron is now campaigning for Britain to remain in a “reformed EU.” The referendum will be a defining moment in the prime minister’s political career.

German Chancellor Angela Merkel

While Britain and Germany have traditionally been EU allies on issues such as free trade, Merkel said Britain staying in the bloc “is the best and most desirable thing for us all.” She has shown strong public support for Cameron, saying in February that his demands to reform the terms of Britain’s EU membership were “justified and necessary.”

Tory Cabinet Minister Boris Johnson

Former London Mayor Boris Johnson is one of the Conservative Party’s most popular politicians – and Cameron’s biggest rival. Many observers believe Johnson is positioning himself as a future prime minister, and that his “Leave” stance and mocking of the EU is part of an opportunistic bid for that power.

U.K. Independence Party Leader Nigel Farage

The U.K. Independence Party (UKIP) was formed in the 1990s with the goal of leading Britain out of the bloc – and so for its leader, the upcoming referendum is a pivotal moment. Farage has come under fire for his anti-immigrant stance – including a recent advertisement showing a queue of migrants and refugees with a slogan that read, “Breaking Point: The EU has failed us all.”

WHAT ABOUT CANADIANS?

The economic impact of Britain leaving the EU could be felt in Canada in a number of ways, according to experts and observers. Here’s a look at how a Brexit could spillover across the Atlantic Ocean:

Even hotter housing

If British voters opt to exit the EU, Canadian homebuyers could feel even more pain.

According to a BMO Capital Markets report, if the “Leave” side prevails in the referendum, global interest rates are likely to remain at historic lows due to uncertainty over the economic future of the U.K. and the EU.

“In that event, the Fed will remain on ice even longer and Canadian rates will again probe all-time lows, keeping mortgage rates at an extremely low ebb and thus further fanning the flames in the domestic housing market,” BMO chief economist Douglas Porter and BMO senior economist Robert Kavcic said in the report, which looked at what’s fueling the white-hot Vancouver and Toronto housing markets.

Will Canadian companies exit after a Brexit?

Canadian businesses that invested in the U.K. to access the European market may have to rethink their strategies if the country decides to leave the EU, Finance Minister Bill Morneau warned at a speech in London on Tuesday.

This means that tens of thousands of jobs at Canadian firms in the U.K. are at risk, Morneau said.

"We're watching in Canada and we're anxious," Morneau said.

"(Canadian businesses) see that the decision they took to invest in the United Kingdom in order to have the opportunity for the European market is now at risk, based on this decision.”

Ontario, Newfoundland could be the biggest provincial losers

While Canada sends only three per cent of its exports to the U.K. – worth about $16 billion last year, according to Statistics Canada – the country is still Canada’s third-largest export market.

In fact, National Bank Financial’s director of public sector research and strategy, Warren Lovely, warns in a report to clients that “a prospective slowing in the already torpid pace of global growth following a ‘Brexit’ is hardly welcome news for a small open economy like Canada.”

Yet not every part of Canada will feel the impact of Britain leaving the EU in the same way.  Newfoundland and Labrador and Ontario are most at risk to potentially weaker export demand from the U.K., Lovely said.  

Nearly seven per cent of Newfoundland and Labrador’s exports and more than five per cent of Ontario’s exports made their way to the U.K. in 2015, according to National Bank. By comparison, Manitoba, Saskatchewan, New Brunswick and Alberta would be the least affected, with each province’s exports to the U.K. making up less than one per cent of its respective totals.

“Little wonder that Ontario’s finance minister has endorsed a strong, united EU,” Lovely said in the note.