Updated

Arguments and allegations are flying as Britons grapple with how to vote in a June 23 referendum on whether to stay in the European Union or walk away.

Opponents say the 28-nation bloc is a bureaucratic behemoth that sucks up billions from British taxpayers while imposing undemocratic laws — even dictating the maximum curvature of bananas. Supporters argue that Britain's prosperity and security benefit from EU membership.

A look at some of the claims by both sides and how they compare with the facts:

CLAIM: The EU makes most of Britain's laws; it even regulates the shape of bananas.

THE FACTS: Opponents of the EU argue that what began in the 1950s as a trading bloc has ballooned in scale and ambition, making policy in areas once reserved for national lawmakers. The group Business for Britain claims that 65 percent of laws introduced in Britain either stem from or are influenced by the EU.

Researchers at the House of Commons Library came up with a much lower figure: 13.2 percent of British legislation introduced between 1993 and 2014 was EU-related. However, the calculation does not include EU regulations that are implemented without the need for new national laws — so the real figure is probably higher, though likely not as high as 65 percent.

As an example of legislative heavy-handedness, Britain's tabloid press loves to cite the claim that the EU bans "bendy bananas" and crooked cucumbers.

A 1994 EU regulation did indeed specify that bananas must be "free from abnormal curvature." EU rules also governed the shape of many other fruits and vegetables — cucumbers, for example, needed to be almost perfectly straight. Many of these specifications were abolished in 2008, though the banana guidelines remain on the books.

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CLAIM: The EU costs British taxpayers almost half a billion dollars a week.

THE FACTS: The figure, cited by anti-EU group Vote Leave, comes from the House of Commons Library, which estimates that Britain paid 17.8 billion pounds to the EU in 2015, roughly 350 million pounds ($490 million) a week.

But Britain got half the money back, including 4.9 billion pounds through a rebate negotiated by then-Prime Minister Margaret Thatcher in the 1980s. The U.K.'s net contribution in 2015 was 8.5 billion pounds — about 165 million pounds ($230 million) a week.

On a per-capita basis, Britain is the eighth-biggest contributor to the EU budget, paying less per head than countries including Germany, the Netherlands and France.

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CLAIM: Britain will be poorer outside the European Union.

THE FACTS: While the economic impact of a British exit — or Brexit — is hard to predict, many economists believe that leaving the EU's tariff-free internal trade and market of 500 million people would be an economic blow.

Trade with EU countries accounted for 45 percent of U.K. exports and 53 percent of imports in 2014. A Brexit would disrupt that trade, at least temporarily, while new agreements were negotiated — a process that could take several years.

The London School of Economics' Center for Economic Policy has calculated that, even if trade barriers with other European countries do not significantly increase, per capita income in Britain will fall by between 1.1 percent and 3.1 percent after a Brexit.

"The possibility of trading more with the rest of the world can't offset the loss of trade with the EU," said the center's Thomas Sampson.

Britain also would likely have to pay into EU funds to secure trade deals with the bloc, as non-EU members Norway and Switzerland currently do.

Some economists, however, say the British economy will benefit if it is freed from EU regulatory shackles and protectionism.

Patrick Minford, professor of applied economics at Cardiff Business School, argues that EU policies supporting agriculture, manufacturing and other sectors prop up unsustainable industries and "warps our economy." He says that Britain — which has been charting a more free-market path than many of its European neighbors since the Thatcherite 1980s — would be better off leaving the EU's protective umbrella and conducting all its trade under World Trade Organization arrangements.

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CLAIM: Britain will be able to control its borders and limit immigration if it leaves the EU.

THE FACTS: As a member of the European Union, Britain must allow citizens of all 27 other member states to live and work in the U.K. Britons can also move abroad, but over the last decade the traffic has been lopsided. The House of Commons Library estimates there are around 1.2 million Britons living in other EU countries, compared with around 3 million EU migrants living in Britain.

If Britain leaves the EU, it would regain the power to stop European Union migrants settling — but that is not the whole story, says Jonathan Portes of the National Institute of Economic and Social Research.

He says a move by Britain to limit or end free movement "will make it very difficult, and maybe impossible, to negotiate the kind of free trade and single-market relationships that many people on the Brexit side want to see." Countries outside the EU that have struck free-trade deals with the bloc, such as Norway and Switzerland, have had to allow EU nationals access to their job markets in return.

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CLAIM: Migrants are drawn to the U.K. by generous welfare benefits, and limiting benefits will reduce immigration.

THE FACTS: EU leaders have agreed to let Britain impose a temporary ban on new arrivals from member states claiming some top-up benefits paid to lower-income workers.

The British government says this will help curb immigration by removing "the 'pull factor' arising from the U.K. benefits system."

But there is little evidence that benefits are a pull factor for migrants. A recent study by the Overseas Development Institute said researchers had found "essentially zero evidence" for the notion that welfare systems pull migrants to wealthy countries. Portes says the National Institute of Economic and Social Research found "no evidence to suggest it's true."

Most economists and policy-makers think wages are a much bigger attraction. Britain's minimum wage is 6.70 pounds ($9.37) an hour, three times the rate in Poland and more than six times that in Romania.

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CLAIM: Leaving the EU will make Britain less safe.

THE FACTS: Many top brass and former military chiefs oppose leaving the EU. A group of former generals, admirals and air marshals said in an open letter that "within the EU, we are stronger" and better able to confront threats including the Islamic State group to growing Russian nationalism. Britain's independent reviewer of terrorism legislation, David Anderson, says EU-wide mechanisms such as the European arrest warrant and passenger-record sharing are effective counter-terror measures.

Others point out that Britain would remain a nuclear power and a member of the NATO alliance if it left the EU. And the U.K.'s security also rests on its close intelligence-sharing relationship with the U.S., which would likely not be affected by EU withdrawal.

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