What is happening?
A referendum is being held on Thursday, 23 June, to decide whether Britain should leave or remain in the European Union. This article is designed to be an easy-to-understand guide - if you have any questions you can send them in using this link. We'll be answering a selection at the bottom of the page.
What is a referendum?
A referendum is basically a vote in which everyone (or nearly everyone) of voting age can take part, normally giving a "Yes" or "No" answer to a question. Whichever side gets more than half of all votes cast is considered to have won.
Why is a referendum being held?
Prime Minister David Cameron promised to hold one if he won the 2015 general election, in response to growing calls from his own Conservative MPs and the UK Independence Party (UKIP), who argued that Britain had not had a say since 1975, when it voted to stay in the EU in a referendum. The EU has changed a lot since then, gaining more control over our daily lives, they argued. Mr Cameron said: "It is time for the British people to have their say. It is time to settle this European question in British politics."
What is the European Union?
The European Union - often known as the EU - is an economic and political partnership involving 28 European countries (click here if you want to see the full list). It began after World War Two to foster economic co-operation, with the idea that countries which trade together are more likely to avoid going to war with each other. It has since grown to become a "single market" allowing goods and people to move around, basically as if the member states were one country. It has its own currency, the euro, which is used by 19 of the member countries, its own parliament and it now sets rules in a wide range of areas - including on the environment, transport, consumer rights and even things like mobile phone charges. Click here for a beginners guide to how the EU works.
Here's a video explaining how the EU works in less than two minutes
What is referendum question?
"Should the United Kingdom remain a member of the European Union or leave the European Union?" Read more: Does the wording of a referendum question matter?
What does Brexit mean?
It is a word that has become used as a shorthand way of saying the UK leaving the EU - merging the words Britain and exit to get Brexit, in a same way as a Greek exit from the EU was dubbed Grexit in the past.
Who will be able to vote?
British, Irish and Commonwealth citizens over 18 who are resident in the UK, along with UK nationals living abroad who have been on the electoral register in the UK in the past 15 years. Members of the House of Lords and Commonwealth citizens in Gibraltar will also be eligible, unlike in a general election. Citizens from EU countries - apart from Ireland, Malta and Cyprus - will not get a vote.
How do you vote?
It will be a similar system to that during other elections. Firstly, if you have registered to vote, you'll be sent a card telling you when voting takes place and where you should go to vote on 23 June. On that day, when you go to the polling station you will be given a piece of paper with the referendum question on it. You then go to a booth, which will have a pencil in it for your use. You then put a X in the box which reflects your choice and put the paper into a ballot box. Alternatively have also been able to opt to vote by post. Read more: Electoral Commission's guide to applying to vote by post.
Didn't David Cameron try and change the rules of the UK's EU membership?
Yes. This was the big news back in January and February as David Cameron sought an agreement with other European Union leaders to change the terms of Britain's membership. He says the deal, which will take effect immediately if the UK votes to remain in the EU, gives Britain "special" status within the 28 nation club, and will help sort out some of the things British people say they don't like about the EU, such as high levels of immigration and giving up the ability to run our own affairs.
Critics say his deal will make little difference and falls well short of what he had promised when he announced his plan for a referendum. Read more: What Cameron wanted v what he got
The main points of the deal are:
- Child benefit - Migrant workers will still be able to send child benefit payments back to their home country - Mr Cameron had wanted to end this practice - but the payments will be set at a level reflecting the cost of living in their home country rather than the full UK rate
- Migrant welfare payments - Mr Cameron says cutting the amount of benefits low paid workers from other EU nations can claim when they take a job in the UK will remove one of the reasons people come to Britain in such large numbers (critics say it will make little difference). He did not get the blanket ban he wanted. New arrivals will not be able to claim tax credits and other welfare payments straight away - but will gradually gain the right to more benefits the longer they stay, at a rate yet to be decided.
- Keeping the pound - Mr Cameron has said Britain will never join the euro. He secured assurances that the eurozone countries will not discriminate against Britain for having a different currency. Any British money spent on bailing out eurozone nations that get into trouble will also be reimbursed.
- Protection for the City of London - Safeguards for Britain's large financial services industry to prevent eurozone regulations being imposed on it
- Running its own affairs - For the first time, there will be a clear commitment that Britain is not part of a move towards "ever closer union" with other EU member states - one of the core principles of the EU. This will be incorporated in an EU treaty change. Mr Cameron also secured a "red card" system for national parliaments making it easier for governments to band together to block unwanted legislation. If 55% of national EU parliaments object to a piece of EU legislation it will be rethought. Critics say it is not clear if this would ever be used in practice.
Who wants the UK to leave the EU?
The British public are fairly evenly split, according to the latest opinion polls. The UK Independence Party, which won the last European elections, and received nearly four million votes - 13% of those cast - in May's general election, campaigns for Britain's exit from the EU. About half of Conservative MPs, including five cabinet ministers, several Labour MPs and the DUP are also in favour of leaving.
Why do they want the UK to leave?
They believe Britain is being held back by the EU, which they say imposes too many rules on business and charges billions of pounds a year in membership fees for little in return. They also want Britain to take back full control of its borders and reduce the number of people coming here to live and/or work. One of the main principles of EU membership is "free movement", which means you don't need to get a visa to go and live in another EU country. They also object to the idea of "ever closer union" and what they see as moves towards the creation of a "United States of Europe".
Who wants the UK to stay in the EU?
Prime Minister David Cameron wants Britain to stay in the EU. Sixteen members of his cabinet also back staying in. The Conservative Party has pledged to be neutral in the campaign - but the Labour Party, SNP, Plaid Cymru and the Lib Dems are all in favour of staying in. US president Barack Obama also wants Britain to remain in the EU, as do other EU nations such as France and Germany. As mentioned above, according to polls, the British public seems pretty evenly split on the issue.
Why do they want the UK to stay?
Those campaigning for Britain to stay in the EU say it gets a big boost from membership - it makes selling things to other EU countries easier and, they argue, the flow of immigrants, most of whom are young and keen to work, fuels economic growth and helps pay for public services. They also believe Britain's status in the world would be damaged by leaving and that we are more secure as part of the 28 nation club, rather than going it alone.
So would Britain be better in or out?
It depends which way you look at it - or what you believe is important. Leaving the EU would be a big step - arguably far more important than who wins a general election - but would it set the nation free or condemn it to economic ruin? Issue-by-issue: The arguments for and against
What about businesses?
Big business - with a few exceptions - tends to be in favour of Britain staying in the EU because it makes it easier for them to move money, people and products around the world. BT chairman Sir Mike Rake, a recent CBI president, says there are "no credible alternatives" to staying in the EU. But others disagree, such as Lord Bamford, chairman of JCB, who says an EU exit would allow the UK to negotiate trade deals as our country "rather than being one of 28 nations". Many small and medium-sized firms would welcome a cut in red tape and what they see as petty regulations. The British Chambers of Commerce says 55% of members back staying in a reformed EU.
What are the rules for campaigning?
The Electoral Commission is in charge of making sure it's a fair contest. It has designated lead campaigns for both the "leave" and "remain" sides. The official campaigns - Vote Leave and Britain Stronger in Europe - get access to a grant of up to £600,000, an overall spending limit of £7m, campaign broadcasts, free mailshots and free access to meeting rooms. The Electoral Commission haspublished a guide to the rules.
So who is leading the rival sides in the campaign?
- Britain Stronger in Europe - the main cross-party group campaigning for Britain to remain in the EU is headed by former Marks and Spencer chairman Lord Rose. It is backed by key figures from the Conservative Party, including Prime Minister David Cameron and Chancellor George Osborne, most Labour MPs, including party leader Jeremy Corbyn and Alan Johnson, who is running the Labour In for Britain campaign, the Lib Dems, Plaid Cymru, the Alliance party and the SDLP in Northern Ireland, and the Green Party. Who is funding the campaign: Britain Stronger in Europe has raised £6.88m so far, boosted by two donations totalling £2.3m from the supermarket magnate and Labour peer Lord Sainsbury. Other prominent Remain donors included hedge fund manager David Harding (£750,000), businessman and Travelex founder Lloyd Dorfman (£500,000) and the Tower Limited Partnership (£500,000). Read a Who's Who guide. Who else is campaigning to remain: The SNP is running its own remain campaign in Scotland as it does not want to share a platform with the Conservatives. Several smaller groups have also registered to campaign.
- Vote Leave - A cross-party campaign that has the backing of senior Conservatives such as Michael Gove and Boris Johnson plus a handful of Labour MPs, including Gisela Stuart and Graham Stringer, and UKIP's Douglas Carswell and Suzanne Evans, and the DUP in Northern Ireland. Former Tory chancellor Lord Lawson and SDP founder Lord Owen are also involved. It has a string of affiliated groups such as Farmers for Britain, Muslims for Britain and Out and Proud, a gay anti-EU group, aimed at building support in different communities. Who is funding the campaign: Vote Leave has raised £2.78m so far. Its largest supporter is businessman Patrick Barbour, who gave £500,000. Former Conservative Party treasurer Peter Cruddas gave a £350,000 donation and construction mogul Terence Adams handed over £300,000. Read a Who's Who guide. Who else is campaigning to leave: UKIP leader Nigel Farage is not part of Vote Leave. His party is running its own campaign. The Trade Union and Socialist Coalition is also running its own out campaign. Several smaller groups have also registered to campaign.
Thanks for sending in your questions. Here are a selection of them, and our answers:
Do I have to register to take part in the EU referendum?
A lot of people asked about this. To be clear, if you are a British, Irish or Commonwealth citizen on the electoral register you will be able to vote in the referendum. You will not have to register specially. You can check with your local authority's electoral services team if you are worried that you are not on the register. If you were not on the register you had until midnight on Thursday, 9 June to submit an application for a vote; this deadline was extended by two days after an online glitch meant people trying to register online in the run up to the original deadline could not do so. For those who are registered to vote the deadlines for applying for a postal vote at the referendum have now gone
Which MPs are for staying and which are for leaving?
The good news for Edward, from Cambridge, who asked this question, is we have been working on exactly such a list. Click here for the latest version..
Will it simply be the case of all votes being counted to give two totals?
Yes, is the answer to this question from William from West Sussex. All the votes will be counted and then added up, with a straight majority needed to provide the result. In answer to some other people's questions, there is no minimum turnout needed. So if, for the sake of argument, only three people voted on the day, if two of them voted to leave, that would be the result.
I'm away on holiday for the week of 23 June - can I still vote?
The good news for Dean from West Sussex - and the many others of you who asked the same question - is that you will be able to vote by post, as people can in local and general elections. Here's the Electoral Commission's guide to applying to vote by post.
When and how will the results be announced?
In answer to a question from John, from Lewes, counts will get under way when polls close at 22:00 GMT Thursday, 23 June at 382 local centres around the UK. These local results will be declared as the counts are completed before being collated at 12 regional centres, which will also declare the totals for each side. There will be a rolling total so the time at which one side reaches the point of being mathematically unbeatable depends on how quickly the vote are counted and how close the results are running. It is a safe bet that from 4am onwards there should be pretty clear picture of which way the vote is going. A chief counting officer will announce the overall result at Manchester Town Hall.
If the UK left the EU would UK citizens need special permits to work in the EU?
Lots of people asked about this. A lot would depend on the kind of deal the UK agreed with the EU after exit. If it remained within the single market, it would almost certainly retain free movement rights allowing UK citizens to work in the EU and vice versa. If the government opted to impose work permit restrictions, as UKIP wants, then other countries could reciprocate, meaning Britons would have to apply for visas to work.
What about EU nationals who want to work in the UK?
As explained in the answer above, it would depend on whether the UK government decided to introduce a work permit system of the kind that currently applies to non-EU citizens, limiting entry to skilled workers in professions where there are shortages.
Would leaving the EU mean we wouldn't have to abide by the European Court of Human Rights?
Duncan, from Chippenham, wanted to know if the UK could deport terror suspects to their own countries to face charges without being overruled by the European Court of Human Rights (ECHR) in Strasbourg.
The ECHR is not a European Union institution. It was set up by the Council of Europe, which has 47 members including Russia and Ukraine. So quitting the EU would not exempt the UK from its decisions.
The UK government is, however, committed to repealing the Human Rights Act which requires UK courts to treat the ECHR as setting legal precedents for the UK, in favour of a British Bill of Rights. As part of that, David Cameron is expected to announce measures that will boost the powers of courts in England and Wales to over-rule judgements handed down by the ECHR.
Has any member state ever left the EU, or would the UK be the first?
Pauline, from Shipston on Stour, asked this one. No nation state has ever left the EU. But Greenland, one of Denmark's overseas territories, held a referendum in 1982, after gaining a greater degree of self government, and voted by 52% to 48% to leave, which it duly did after a period of negotiation. The BBC's Carolyn Quinnvisited Greenland at the end of last year to find out how they did it.
If we stay in do we keep the pound for ever?
It is up the UK government to decide whether or not to keep the pound or switch to the euro. The deal David Cameron struck with the EU included recognition that the UK has no plans to switch to the euro currency.
How much does the UK contribute to the EU and how much do we get in return?
In answer to this query from Nancy from Hornchurch - the UK is one of 10 member states who pay more into the EU budget than they get out, only France and Germany contribute more. In 2014/15, Poland was the largest beneficiary, followed by Hungary and Greece.
The UK also gets an annual rebate that was negotiated by Margaret Thatcher and money back, in the form of regional development grants and payments to farmers, which added up to £4.6bn in 2014/15. According to the latest Treasury figures, the UK's net contribution for 2014/15 was £8.8bn - nearly double what it was in 2009/10.
The National Audit Office, using a different formula which takes into account EU money paid directly to private sector companies and universities to fund research, and measured over the EU's financial year, shows the UK's net contribution for 2014 was £5.7bn. Read more number crunching from Reality Check.
If I retire to Spain or another EU country will my healthcare costs still be covered?
David, from East Sussex, is worried about what would happen to his retirement plans if Britain votes to leave the EU. This is one of those issues where it is not possible to say definitively what would happen. At the moment, the large British expat community in Spain gets free access to Spanish GPs and their hospital treatment is paid for by the NHS. After they become permanent residents Spain pays for their hospital treatment. Similar arrangements are in place with other EU countries.
If Britain leaves the EU but remains in the single market, or the European Economic Area as it is known, it might be able to continue with this arrangement,according to a House of Commons library research note. If Britain has to negotiate trade deals with individual member states, it may opt to continue paying for expats' healthcare through the NHS or decide that they would have to cover their own costs if they continue to live abroad, if the country where they live declines to do so.
Will the opinion polls get it wrong again?
The short answer is that we'll find out on 24 June! John wrote to ask whether we are in for a repeat of the general election when the opinion polls underestimated support for one side, the Conservatives, and overstated support for the other, Labour. As John points out, research suggests younger people are more likely to vote to remain in the EU, while older voters tend to favour out. But as a general rule, older people are more likely to vote in elections than younger people. The "don't knows" are also running at between 17% and 20%. Prof John Curtice, who supervised the general election exit poll, has also noticed a difference between polls conducted online, which suggest the race is close, and ones conducted over the telephone, which put the Remain campaign ahead. Opinion polling is not an exact science - for more information on the latest referendum polls and analysis by Prof Curtice, visit the National Centre for Social Research's What UK thinks site.
Who counts as a British citizen?
Jude wanted to know if his Peruvian girlfriend, who is a British citizen but has been living in Peru for five years, can take part in the referendum. The answer is yes, if she has appeared on the UK electoral register in the past 15 years.
How long will it take for Britain to leave the EU?
This was a question asked by many people. The minimum period after a vote to leave would be two years. During that time Britain would continue to abide by EU treaties and laws, but not take part in any decision-making, as it negotiated a withdrawal agreement and the terms of its relationship with the now 27 nation bloc. In practice it may take longer than two years, depending on how the negotiations go.
Could MPs block an EU exit if Britain votes for it?
Michael, from East Sussex asks an intriguing question - could the necessary legislation pass the Commons if all SNP and Lib Dems, nearly all Labour and many Conservative MPs were in favour of staying?
The answer is that technically MPs could block an EU exit - but it would be seen as political suicide to go against the will of the people as expressed in a referendum. The referendum result is not legally binding - Parliament still has to pass the laws that will get Britain out of the 28 nation bloc, starting with the repeal of the 1972 European Communities Act.
The withdrawal agreement would also have to be ratified by Parliament - the House of Lords and/or the Commons could vote against ratification, according to a House of Commons library report.
It adds: "If the Commons resolves against ratification, the treaty can still be ratified if the Government lays a statement explaining why the treaty should nonetheless be ratified and the House of Commons does not resolve against ratification a second time within 21 days (this process can be repeated ad infinitum)."
In practice, Conservative MPs who voted to remain in the EU would be whipped to vote with the government. Any who defied the whip would have to face the wrath of voters at the next general election.
One scenario that could see the referendum result overturned, is if MPs forced a general election and a party campaigned on a promise to keep Britain in the EU, got elected and then claimed that the election mandate topped the referendum one. Two thirds of MPs would have to vote for a general election to be held before the next scheduled one in 2020.
What is the single market?
Virginia, from Hayling Island, asked several questions around the concept of the single market. You could probably write a book on this one. But we'll try to keep it brief. The single market is seen by its advocates as the EU's biggest achievement and one of the main reasons it was set up in the first place. Britain was a member of a free trade area in Europe before it joined what was then known as the common market. In a free trade area countries can trade with each other without paying tariffs - but it is not a single market because the member states do not have to merge their economies together.
The European Union single market, which was completed in 1992, allows the free movement of goods, services, money and people within the European Union, as if it was a single country. It is possible to set up a business or take a job anywhere within it. The idea was to boost trade, create jobs and lower prices. But it requires common law-making to ensure products are made to the same technical standards and imposes other rules to ensure a "level playing field". Critics say it generates too many petty regulations and robs members of control over their own affairs. Mass migration from poorer to richer countries has also raised questions about the free movement rule. Read more: A free trade area v EU single market
What will happen to protected species if Britain leaves the EU?
Dee, from Launceston, wanted to know what would happen to EU laws covering protected species such as bats if Britain left. The answer is that they would remain in place, initially at least. After a leave vote, the government would probably review all EU-derived laws in the two years leading up to the official exit date to see which ones to keep or scrap.
The status of Special Areas of Conservation and Special Protection Areas, which are designated by the EU, would be reviewed to see what alternative protections could be applied. The same process would apply to European Protected Species legislation, which relate to bats and their habitats.
The government would want to avoid a legislative vacuum caused by the repeal of EU laws before new UK laws are in place - it would also continue to abide by other international agreements covering environmental protection.
How much money will the UK save through changes to migrant child benefits and welfare payments?
Martin, from Poole, in Dorset, wanted to know what taxpayers are likely to get back from the benefit curbs negotiated by David Cameron in Brussels. We don't exactly know because the details have not been worked out. HM Revenue and Customs have suggested about 20,000 EU nationals receive child benefit payments in respect of 34,000 children in their country of origin at an estimated cost of about £30m.
But the total saving is likely to be significantly less than that because Mr Cameron did not get the blanket ban he wanted. Instead, payments will be linked to the cost of living in the countries where the children live. David Cameron has said that as many as 40% of EU migrant families who come to Britain could lose an average of £6,000 a year of in-work benefits when his "emergency brake" is applied. The DWP estimates between 128,700 and 155,100 people would be affected. But the cuts will be phased in. New arrivals will not get tax credits and other in-work benefits straight away but will gradually gain access to them over a four year period at a rate yet to be decided.
If we leave the EU does it mean we would be barred from the Eurovision Song Contest?
Sophie from Peterborough, who asks the question, need not worry. We have consulted Alasdair Rendall, president of the UK Eurovision fan club, who says: "No, we would not be barred. All participating countries must be a member of the European Broadcasting Union. The EBU - which is totally independent of the EU - includes countries both inside and outside of the EU, and also includes countries such as Israel that are outside of Europe. Indeed the UK started participating in the Eurovision Song Contest in 1957, 16 years before joining the then EEC."
Do Commonwealth citizens resident in the UK on a limited work visa get to vote?
Brendan, from London, wonders whether Commonwealth citizens need to have been granted indefinite leave to remain to get a vote. The Electoral Commission guidelines say: "Any type of leave to enter or remain is acceptable, whether indefinite, time limited or conditional." That means all citizens of India, Australia, Pakistan, Canada and 48 other Commonwealth nations who are living in the UK can take part (provided they are old enough and are on the electoral register). As can citizens of British overseas territories, such as the Falkland Islands, Bermuda or Gibraltar, if they are currently residing in the UK. Here is a full list of Commonwealth countries.
Can EU citizens who are resident in the UK and on the electoral roll vote in the referendum?
Philip, from Kriton in Lindsey, North Lincolnshire, asked this. The answer is no, unless you are an Irish, Malta or Cyprus citizen. The rules are the same as for a general election, when EU citizens living in the UK are not allowed to take part. So they will not get a polling card and not be on the list at the polling station.
What impact would leaving the EU have on house prices?
John, in London, is concerned about what will happen to house prices if Britain leaves the EU and "millions of EU citizens need to leave" creating a flood of available housing. This is one of those questions where there is no clear-cut factual answer. But we can say that none of the main players are suggesting that citizens of other EU countries will be "sent packing" (to use John's phrase) after a Leave vote. There are a host of other variables that have an impact on property prices, including things like interest rates and the general state of the economy. But expect this to be one of those issues fought over by both sides during the campaign.
What is the 'red tape' that the opponents of the EU go on about?
Ged, from Liverpool, suspects "red tape" is a euphemism for employment rights and environmental protection. According to the Open Europe think tank, four of the top five most costly EU regulations are either employment or environment-related. The UK renewable energy strategy, which the think-tank says costs £4.7bn a year, tops the list. The working time directive (£4.2bn a year) - which limits the working week to 48 hours - and the temporary agency workers directive (£2.1bn a year), giving temporary staff many of the same rights as permanent ones - are also on the list.
There is nothing to stop a future UK government reproducing these regulations in British law, if the country left the EU. And the costs of so-called "red tape" would not necessarily disappear overnight in the event of an exit - if Britain opted to follow the "Norway model" and remained in the European Economic Area most of the EU-derived laws would remain in place.
Would Britain be party to the Transatlantic Trade and Investment Partnership if it left?
Ste, in Bolton, asked about this. The Transatlantic Trade and Investment Partnership - or TTIP - currently under negotiation between the EU and United States will create the biggest free trade area the world has ever seen. Cheerleaders for TTIP, including David Cameron, believe it could make American imports cheaper and boost British exports to the US to the tune of £10bn a year. But many on the left, including Labour leader Jeremy Corbyn, fear it will shift more power to multinational corporations, undermine public services, wreck food standards and threaten basic rights. Quitting the EU would mean the UK would not be part of TTIP. It would have negotiate its own trade deal with the US.
What impact would leaving the EU have on the NHS?
Paddy, from Widnes, wanted to know how leaving the EU would affect the number of doctors we have and how it would impact the NHS. This became an issue in the referendum debate after the Leave campaign claimed the money Britain sends to the EU, which it claims is £350m a week, could be spent on the NHS instead. The BBC's Reality Check team looked into this claim. Health Secretary Jeremy Hunt has warned that leaving the EU would lead to budget cuts and an exodus of overseas doctors and nurses. The Leave campaign dismissed his intervention as "scaremongering" and continues to insist that EU membership fees could be spent on domestic services like the NHS. Former Labour health secretary Lord Owen has said that because of TTIP (see answer above) the only way to protect the NHS from further privatisation was to get out of the EU.
Can you only use a pencil to vote?
Mandy, from Sutton-in-Ashfield, asked this one - and the answer is no. You can use a pen, if you want. But electoral law states that clerks must provide pencils in polling booths.
If I spoil my ballot paper or abstain, will the vote be counted for Remain?
Alan, from Stockport, and Paul, from the Isle of Wight, and quite a few others, sent invariations of this question. And the short answer is, no. A ballot paper will only be counted if it contains a cross in either the box for Remain, or in the box for Leave. Anything else - for example, more than one cross, a cross outside the box, or a blank ballot paper - will be deemed invalid. The side that wins is the one with the most legible votes. Tim, from Epsom, wanted to know what would happen if 49% voted for one side, 48% for the other side with 3% spoilt ballots. Because the spoilt ballots would not count as votes, they would therefore not be counted as part of the final result.
Will I still be able to use my passport?
Yes, in answer to Ruth's question. It is a British document - there is no such thing as an EU passport, so whether the UK stays in or leaves the EU your passport will stay the same. In theory, the government could, if it wanted, decide to change the colour, which is currently standardised for EU countries, says the BBC's Europe correspondent, Chris Morris.
Will our EHIC cards still be valid?
No-one knows for definite. The EHIC card - which entitles travellers to state-provided medical help for any condition or injury that requires urgent treatment, in any other country within the EU, as well as several non-EU countries - is not an EU initiative. It was negotiated between countries within a group known as the European Economic Area, often simply referred to as the single market (plus Switzerland, which confusingly is not a member of the EEA, but has agreed access to the single market). Therefore, the future of Britons' EHIC cover could depend on whether the UK decided to sever ties with the EEA in the event of a leave vote.
If we left the EU, would cars need new number plates?
Probably not, says BBC Europe correspondent Chris Morris, because there's no EU-wide law on vehicle registration or car number places, and the EU flag symbol is a voluntary identifier and not compulsory. The DVLA says there has been no discussion about what would happen to plates with the flag if the UK voted to leave.
If the UK left the EU, would it be able to rejoin in the future?
A few people have asked this question - and the answer is yes. BBC Europe editor Katya Adler says the UK would have to start from scratch with no rebate, and enter in to accession talks with the EU. Every member state would have to agree to the UK re-joining. But she says with elections looming elsewhere in Europe, other leaders might not be generous towards any UK demands.
The mechanisms for re-joining the EU are set out in the Lisbon Treaty. According to Article 50: "If a state which has withdrawn from the Union asks to rejoin, its request shall be subject to the procedure referred to in Article 49."
And Article 49 states: "The applicant state shall address its application to the Council, which shall act unanimously after consulting the Commission and after receiving the assent of the European Parliament, which shall act by an absolute majority of its component members. The conditions of admission and the adjustments to the Treaties on which the Union is founded, which such admission entails, shall be the subject of an agreement between the member states and the applicant state."
New members are required to adopt the euro as their currency, once they meet the relevant criteria, although the UK could try to negotiate an opt-out.
Would the EU still use English, if the UK voted to leave?
Yes, says BBC Europe editor Katya Adler. There would still be 27 other EU states in the bloc, and others wanting to join in the future, and the common language tends to be English - "much to France's chagrin", she says.
Is EU referendum polling harder or easier than in an election?
On the one hand, it's easier as there are only two options, says BBC home editor Mark Easton. But it's also harder because polling companies' expertise has been based on the general election model and built up over many years.
Would a Brexit harm product safety?
Probably not is the answer. It would depend on whether or not the UK decided to get rid of current safety standards. Even if that happened any company wanting to export to the EU would have to comply with its safety rules, and it's hard to imagine a company would want to produce two batches of the same products.