Brexit and the EU referendum: Who should you believe?

With the competing sides issuing wildly differing claims about everything from the cost of membership to the impact on trade and immigration, many people are understandably confused about what the actual facts are.

A new report, jointly compiled by academics from The UK in a Changing Europe and the information service Full Fact, accused both sides of playing fast and loose with the truth.

The Leave and Remain camps vying for the upper hand in the referendum campaign have been putting out misleading and inaccurate statements, says the report.

A key pro-Brexit assertion that Britain sends £350 million a week to Brussels is wrong, according to the survey because it does not take into account the rebate the UK receives on its contributions.

And pro-Remain claims by the CBI that membership of the EU is worth £3,000 a year to every household is "not credible", says the study.

This is because the data used for the calculation is based on a selection of studies produced at different times – some more than a decade old – with different methodologies, the study decided.

Full Fact director, Will Moy, said: "Our mission is to cut through the rhetoric and arm people with the facts, by providing impartial, independent analysis. Whichever side they end up on, it is very important that they are able to access reliable information from an impartial source."

However, even this report comes with something of a health warning. While Full Fact claims to be a "non-partisan" group campaigning against "inaccuracy in the media", media commentator Andrew Gilligan has called this into question, pointing out that in 2011it was refused registration as a charity after another judge heard that it lacked the "requisite objectivity" and was not "established for the public benefit".

Nobody said getting to the bottom of the debate would be easy.

Economic costs and benefits

The Leave campaign says the EU costs the average UK household as much as £9,265 a year, whereas the pro-EU CBI claims that economic benefits that come from membership are worth £3,000 per year to every household.

The report says that both of these statements are misleading.

"The CBI figure of £3,000 quoted by Remain campaigners is not a credible estimate," says UK in a Changing Europe's Jonathan Portes.

"It is based on a selection of studies produced at different times – some date back well over a decade – using different methodologies, and designed to answer different questions."

However, if the CBI figure is considered unreliable because of its use on disparate data, the pro-Brexit figure also comes under criticism for being based on a single study.

The figure assumes that on leaving the EU, the UK would remove all barriers to trade with the rest of the world, and abolish all EU regulations in areas like the environment and the labour market.

Mr Portes says the general consensus among economists is that there will be some cost to leaving the EU.

"The estimates range from close to zero in one model, if we continue to be part of the single market, keep allowing free movement of Labour from the EU and so on, to significantly negative if leaving results in substantial new barriers to trade," says the report.

Security

Those campaigning to leave the EU argue that the border-free Schengen arrangement makes it easier for terrorists and criminals to travel across Europe, while EU supporters argue that working with our closest neighbours makes it easier to tackle these threats.

Professor Richard Whitman says in practice leaving the EU is unlikely to make much difference one way or the other.

He says Britain, which is not a member of Schengen, has retained full border controls and applies the same rules to arrivals from both within the EU and outside.

"Outside the EU, the UK would be free to decide on which issues and with which issues and with which countries it would wish to pursue such co-operation," says Prof Whitman.

"The UK already collaborates with other countries outside the EU, on these issues."

Immigration

Brexit supporters argue that leaving the EU will be the only way we can take control of immigration, while EU supporters argue that the number of Britons living in other EU countries almost offsets the number of immigrants to Britain.

The report says it is true that as long as Britain remains in the EU, we will have limited control over immigration from other EU countries.

However, it also points out that non-EU countries which participate in the single market, such as Norway and Switzerland, also have to accept EU immigration.

"Leaving the EU would not automatically lead to a large reduction in immigration," it says.

"Norway and Switzerland both have higher immigration per head than the UK," says the report. "Controlling immigration might require leaving the single market as well as the EU."

It has also been argued that leaving the EU might increase immigration from non-EU countries.

Exports

The Leave campaign argues that as the EU sells more to us than we do to them, the remaining member states would want to continue trading with us to retain the British market. The other side of this coin, as presented by the Remain camp, is that while half of our exports go to the EU, while the British market accounts for just five per cent of exports from Europe

The report says it is difficult to predict what trade deals would be drawn up if Britain quite the EU.

"Leave campaigners are undoubtedly correct in claiming that it would be in the interests of the EU, at least economically, to conclude some form of free trade deal, especially for trade in goods," it says.

"But that does not mean it would happen. After all economists generally think that free trade deals are in the interests of both countries, but that doesn't necessarily mean they come about."

Laws imposed on the UK

Eurosceptics claim that between 1993 and 2014, 64.7 per cent of laws were influenced by the EU, while EU regulations accounted for 59.3 per cent of all legislation. Those calling for Britain to remain in the EU say the figure is just 13.2 per cent.

The lower figure is based on the number of Acts of Parliaments, and detailed rules known as "statutory instruments." It does not, however, include EU regulations which are imposed automatically. If these are added into the equation, it takes the proportion to about 50 per cent.

But most of these regulations, brought in by the European Commission, have no bearing on the UK.

Professor Damian Chalmers suggests that the best measure would be to take all legally binding EU rules, and compare them to all legally binding rules in the UK.

"We could then set these against the total number of EU rules passed: 1,758 in 2014, plus 637 which amended previous laws," he says.

"This is a big figure, but almost certainly a small proportion of the total number of rules passed in the UK."

Cost of membership

Leave campaigners claim the EU sends £350 million to Brussels each week, or £18 billion every year, while the Remain camp argues the annual cost is just £5.29 billion.

"The claim that the UK sends £350 million per week to the EU is wrong," says the report. "That is what we would send if it wasn't for the UK's budget rebate."

The report says the figure will vary from year to year, but last year it was about £250 million a week. However, the UK gets a chunk of this money back in the form of grants, which mainly go to farmers and the poorest parts of the UK including Wales and Cornwall.

The Remain camp argues that these grants reduce the net cost of EU membership to £9 billion, and further argues that in order to access the EU single market in the same way that Switzerland does, Britain would have to pay a further £3.71 billion. which is where the £5.29 billion figure comes from. The report describes this as speculation.

"There are no figures on Switzerland's contribution more recently than 2009," the report says. "It's hard to say whether or not that is the case, and we don't know whether a newly departed UK would want or could get a deal similar to the Swiss."