If it's difficult to understand why the United Kingdom would vote to leave the European Union, spawning deep uncertainty about what happens next on any number of fronts, look no further than immigration. 

The Brexit result was, in large part, a reaction to growing anxieties over migration to the U.K., realistic or not.

Immigration was a top priority for voters in the Leave camp, according to pre-referendum polling, and Leave leaders like the U.K. Independence Party's Nigel Farage and former London mayor and likely next prime minister Boris Johnson have been clear on their position that "taking back control" of the U.K.'s borders is critical to future economic health. 

It was a deliberate strategy to target migrants and the nostalgic whims of Britons "longing for a time and place that never was," said Geoff Smith, professor emeritus of history at Queen's University in Kingston, Ont. 

"There's an unhappiness with the status quo and the tendency has been to blame it on migrants," Smith said. "They became a scapegoat, and it worked."

Part of that scapegoating has been to point the finger at migrants for the U.K.'s slow and disappointing recovery from the financial crisis of 2008, as well as for disappearing public services, especially in places outside of major urban centres.

The Leave campaign fomented that resentment, Smith said, adding that nationalist parties in countries such as France, Netherlands and Italy are keeping close tabs on the strategy. 

It is slightly concerning, no matter what your take on Brexit, that no one really knows what's going to happen next in terms of migration to the U.K. — not even the Leave leaders. 

Scale of migration to U.K. has intensified

But to grasp why a majority of those who voted in the referendum would cast a ballot for the uncertainty, turmoil and isolation that comes with divorcing the EU, it's vital to look at the last two decades of immigration to the U.K. 

Those years brought an influx of migrants from outside the EU free-travel zone, from countries like India and Pakistan, but also from economically deprived countries of eastern Europe that were formerly part of the communist-controlled Eastern Bloc. 

Nigel Farage Brexit EU Britain

The bellicose orator Nigel Farage, leader of the U.K. Independence Party, helped lead the Leave campaign to victory. For years, Farage and UKIP operated on the margins, building support among Euro-skeptics. In the last general election they won four million votes, the highest ever for the party. (Jeff J Mitchell/Getty)

The number of foreign-born people living in the U.K., for example, more than doubled in that time, from 3.8 million in 1993 to about 8.3 million in 2014

Statistics released a few weeks before the vote that showed net migration to the U.K. had reached 333,000 in 2015 were thought to be an essential factor in the Leave win. 

"The patterns and scale of migration have changed significantly over the past two decades and it really picked up pace in the last decade," said Will Somerville, a senior fellow at the Migration Policy Institute.

'Anxious at the sheer speed of change'

Some working-class Britons see eastern European migrants mainly as cheap labour that moves freely into the U.K., keeping wages stagnant and reliable work out of reach. Add in lingering anger over the U.K.'s sluggish economy and a tabloid press that has pushed a toxic narrative around migration and the picture becomes a bit clearer. 

Nigel Farage breaking point sign Brexit

Farage was criticized by his opponents throughout the campaign for using deliberately misleading imagery and stirring up anti-immigration sentiment. He says that the U.K. can't solve its internal problems without taking control of the border, and to do that, the U.K. must leave the EU. (Daniel Leal-Olivas/Getty)

Interestingly, the Leave camp won support across a diverse subsection of voters, both politically and economically. The clearest factor seemed to be education: those with a university degree voted overwhelmingly to remain, while those without one did the opposite, according to the Guardian newspaper.

Of course, not everyone who voted Leave is a xenophobe. Somerville said the Leave side managed to capture support from what he calls "the big, anxious middle" — a cross-section of voters who have lost confidence in the government and are also distrustful of policies dictated by Eurocrats in Brussels. 

"They're worried about the government's lack of competence, the pressure immigration puts on public services and they're anxious at the sheer speed of change," Somerville said. 

Then there are those who may have voted Leave simply to stick it to the political elite both in London and Brussels. After all, Prime Minister David Cameron called the referendum to settle an internal party beef, assuming an easy victory. 

'It feels like they've been rejected'

Of course, there likely won't be any major changes in immigration policy for at least two years as the U.K. negotiates its contentious break with the EU, said Willem Maas, an associate professor of political science at York University. 

Brexit protester

A pro-European Union demonstrator holds a sign in London, protesting Britain's decision to leave the EU. (Marc-André Cossette/CBC)

"Free movement of people is a major point of European integration," said Maas. "The leaders of the 27 other member states are not just going to roll over and die on this issue."

But worry among European nationals and other immigrants living in the U.K. and how this might change life for them and their families is already apparent. 

While he doesn't have any hard data yet, Somerville said it's pretty clear that the immigrant population, no matter what the U.K.'s policies look like once it has left the EU, has only been further disenfranchised by the vote. That appears to be especially true among young people, who voted overwhelmingly to remain in the EU.

Boris Johnson EU Brexit Britain

Former London mayor and Leave campaigner Boris Johnson has had a tough week. He told reporters that a convoluted editorial he penned outlining what a Brexit will look like was hastily put together and that he should have slept more before writing it. (Stefan Rousseau/Reuters)

"They're concerned about what this means for them and their identity and their connection to Britain. It feels like they've been rejected," says Somerville. "It's not a spitting anger, but rather a deep sadness," adding that it would be "hugely surprising" if Downing Street didn't impose restrictions and controls on European migrants some time in the next few years. 

Whatever the end result, the anti-immigration message that accompanied much of the Leave camp's rhetoric is likely to cause divisions in the U.K.'s national fabric for years to come. 

"So now they've taken it all apart," said Smith. "The question is, how in the hell are they going to put it all back together again?"