There’s a consensus that is growing among some British citizens around immigration: they don’t want it.

A recent Washington Post headline read “British welcome of immigrants wears thin,” and detailed a growing fear in the United Kingdom that their nation is sinking under the weight of too much immigration.

The fear isn’t without impetus. The European Union allows free movement between member nations and temporary immigration restrictions on two of the region’s poorest countries — Romania and Bulgaria — were lifted on January 1.

The worries over benefits have given politicians like Nigel Farage, leader of the UK Independence Party, which favors stricter immigration controls, the opportunity to capitalize on fears over the opening of Europe to new member states.

Farage told the Post that he expects more than 50,000 Romanian and Bulgarian immigrants to come to the UK now that restrictions have been lifted, since those immigrants could be “making 40 quid a day [about $65] begging on the streets of London, which is what you make in a month in Bucharest.”

Why are Britains worried? Here’s a breakdown:

1. Economic Disparity

There’s a sizable divide between the economies of the rich and poor in Europe. Workers in Britain earned nine times more than their Bulgarian counterparts in 2011 and seven times more than those in Romania, according to data from Eurostat, the body that gathers data for the EU’s executive arm, the European Commission

That has sparked fears that a wave of immigration could crash down on the UK.

2. The Dole

Once a citizen of a European Union member state establishes residency in a different country, that person is entitled to the benefits provided by that nation to its citizens.

In Britain, as opposed to other European countries, the worry over immigration is less cultural, and more closely linked to worries about the cost associated with benefits.

That’s spelled out in a study released earlier this month by Ipsos MORI, a market research company in the UK and Ireland.

Here’s how the UK compares to other European countries when it comes to concern over benefits:

3. Opposition to the European Union

If there was ever a honeymoon among EU members, it’s over. The lame European economy in recent years has given rise to anti-EU political parties across the continent, and Britain is no different.

“In the UK specifically, that immigration skepticism is mixed with a skepticism about the European Union, and that’s manifested mostly in the debates on free movement,” said Elizabeth Collett, director of the Migration Policy Institute Europe, in a phone interview. “This idea that the UK is apparently losing out from its partnership with Europe and that some changes need to be made.”

Collett says that the public dialogue in Britain doesn’t fully account for the ways the nation benefits from immigration.

“There’s a gap I think also between the empirical realities of migration to the UK… and the perception in politics,” she said. “And that gap has widened.”

4. Employment and Wages

The British who want lower levels of immigration are also concerned about the impact of newcomers on their country’s labor market.

There’s little doubt that immigration helps add billions of dollars each year to the British gross domestic product, the overall economic output of a nation.

But a bigger worry for citizens would be employment and wages.

The Ipsos MORI report found that even as the number of foreign-born workers in the UK increased in recent years, wages and earnings remained relatively stable.

Overall impact on wages was small, “there may be some downward pressures on the low wage market where many new migrants tend to find work,” according to an analysis cited in the report.

5. Bad Memories

Britain has reason to be nervous about an influx of new immigrants.

In 2004, 10 new member countries mostly located in Eastern Europe entered the European Union.

That created a unique rush of immigrants into Britain, according to MPI Europe’s Collett.

“When Poland, Hungary, Czech Republic and all the other new member states acceded to the union, the UK, Sweden and Ireland were the only three countries to lift arrangements immediately, which meant that there were very few options for those new member state workers who wanted to move abroad,” she said.

“As a result, a large number of people arrived in 2004 in the UK, much larger than the government expected, so they are almost dealing with this history when they are dealing with Romania and Bulgaria.”

Of course, the situation is different this time around. Now, Romanians and Bulgarians will be able to move to any nation in the European Union, instead of just three select countries.

6. Prejudice

Opponents of immigration in the UK mainly fear economic damage, but xenophobia likely plays a role too.

Both Bulgaria and Romania are home to populations of Roma, travelers who have been largely ostracized in communities across Europe.

The tensions between Slovakian Roma immigrants and British citizens played out in the English city of Sheffield last November. Residents in a working-class area began community patrols — what some called vigilantism — to monitor the activity of Roma immigrants.

A member of Parliament representing Sheffield, David Blunkett, told the BBC at the time that tension were like “a boiling pot.”

“We have got to change the behavior and the culture of the incoming community, the Roma community, because there’s going to be an explosion otherwise,” he said. “We all know that.”

British tabloid certainly didn’t help calm matters with headlines like “Roma migrant invasion will start UK riots,” which led the Daily Star.

Still, the main motivation for blocking immigration is “less of a cultural issue and more of a numbers issue,” according to Collett.

The Takeaway: When the economy tanks, people start looking for answers. In Britain, some have blamed immigrants and immigration, but the overall picture of economic growth shows a negligible impact on wages. The recent history of immigration to the UK, with the big spike in 2004, makes it understandable that the British might fear another rush. But considering citizens of the two new member states can go anywhere in the EU, a repeat wave seems unlikely.