Brexit: All you need to know about the UK leaving the EU
Here is an easy-to-understand guide to Brexit - beginning with the basics, then a look at the current negotiations, followed by a selection of answers to questions we've been sent.
What does Brexit mean?
It is a word that is used as a shorthand way of saying the UK leaving the EU - merging the words Britain and exit to get Brexit, in the same way as a possible Greek exit from the euro was dubbed Grexit in the past. Further reading: The rise of the word Brexit
Why is Britain leaving the European Union?
A referendum - a vote in which everyone (or nearly everyone) of voting age can take part - was held on Thursday 23 June, 2016, to decide whether the UK should leave or remain in the European Union. Leave won by 51.9% to 48.1%. The referendum turnout was 71.8%, with more than 30 million people voting.
Find the result in your area
What was the breakdown across the UK?
England voted for Brexit, by 53.4% to 46.6%. Wales also voted for Brexit, with Leave getting 52.5% of the vote and Remain 47.5%. Scotland and Northern Ireland both backed staying in the EU. Scotland backed Remain by 62% to 38%, while 55.8% in Northern Ireland voted Remain and 44.2% Leave. See the results in more detail.
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 were 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 such as mobile phone charges. Click here for a beginners' guide to how the EU works.
When is the UK due to leave the EU?
The UK had been due to leave on 29 March 2019, two years after it started the exit process by invoking Article 50 of the EU's Lisbon Treaty. But the withdrawal agreement reached between the EU and UK has been rejected three times by UK MPs.
Having granted an initial extension of the Article 50 process until 12 April 2019, EU leaders have now backed a six-month extension until 31 October 2019. However, the UK will leave before this date if the withdrawal agreement is ratified by the UK and the EU before then.
So is Brexit definitely happening?
As things stand, the UK is due to leave the European Union at 23:00 GMT on 31 October 2019. If the UK and EU ratify the withdrawal agreement before then, the UK will leave on the first day of the following month.
But could Brexit be cancelled?
Yes. Stopping Brexit would require a change in the law in the UK, something neither the government nor the main UK opposition parties want to do at this point. The European Court of Justice ruled on 10 December 2018 that the UK could cancel the Article 50 Brexit process without the permission of the other 27 EU members, and remain a member of the EU on its existing terms, provided the decision followed a "democratic process", in other words, if Parliament voted for it. In March, an online petition calling for Article 50 to be revoked gained over six million signatures.
Could Brexit be delayed?
Theresa May has said she wants the UK to leave the EU as soon as possible, if possible by 22 May, so the UK will not have to take part in the European Parliament elections taking place across Europe that month. The EU has said the Brexit process should not be extended again beyond 31 October 2019, but legally speaking another extension could happen if all EU countries, including the UK, agree to it.
Could there be another referendum?
It would have to be put into law by the government, which has previously ruled it out. But having failed three times to get MPs to support her withdrawal deal, Theresa May has held talks with Jeremy Corbyn about finding a way forward. Some Labour MPs want Mr Corbyn to make a "confirmatory vote" on any deal a condition of any agreement. If Labour and the Conservatives fail to reach an agreement, MPs will face a series of votes on Brexit options, which could include another referendum. Mrs May has said her government "stands ready to abide by the decision of the House" if Labour does the same. MPs have twice rejected a "confirmatory vote" in Commons votes although the second attempt saw an increased number back it.
Why do politicians want a deal?
The main point of having a deal between the UK and the EU is to ensure as smooth as possible an exit from the EU for businesses and individuals - and to allow time for the two sides to hammer out a permanent trading relationship.
What is in Theresa May's deal with the EU?
After months of negotiation, the UK and EU agreed a Brexit deal. It comes in two parts.
A 585-page withdrawal agreement. This is a legally-binding text that sets the terms of the UK's divorce from the EU. It covers how much money the UK owes the EU - an estimated £39bn - and what happens to UK citizens living elsewhere in the EU and EU citizens living in the UK. It also proposes a method of avoiding the return of a physical Northern Ireland border.
A 26-page statement on future relations. This is not legally-binding and sketches out the kind of long-term relationship the UK and EU want to have in a range of areas, including trade, defence and security.
What is the transition period?
This is part of the withdrawal agreement, which so far, has not been approved by MPs. It refers to a period of time after Brexit until 31 December, 2020 (or possibly later), to get everything in place and allow businesses and others to prepare for the moment when the new post-Brexit rules between the UK and the EU begin. It would also allow more time for the details of the new relationship to be fully hammered out. Free movement would continue during the transition period, as the EU wanted. The UK would be able to strike its own trade deals - although they wouldn't be able to come into force until 1 January 2021. But it all rests on the withdrawal deal being ratified.
- Further reading: UK and EU agree transition deal terms
- In a lot of depth: The 129-page draft withdrawal agreement
Could we leave without a deal?
Yes. This is the so-called no-deal Brexit.
What would happen if the UK left without a deal?
The UK would sever all ties with the EU with immediate effect, with no transition period and no guarantees on citizens' rights of residence. The government fears this would cause significant disruption to businesses in the short-term, with lengthy tailbacks of lorries at the channel ports, as drivers face new checks on their cargos. Food retailers have warned of shortages of fresh produce and the NHS is stockpiling medicines, in case supplies from EU countries are interrupted. Government ministers and multinational companies with factories in the UK have also warned about the long-term impact on the British economy. Brexit-supporting MPs claim it would not be as bad as they say and the UK would save on the £39bn divorce bill, as well as being free to strike its own beneficial trade deals around the world.
Would trade with the EU continue?
The World Trade Organization sets rules for countries that don't have free trade deals with each other, including tariffs - the taxes charged on the import of goods. Without an agreement on trade, the UK would trade with the EU under World Trade Organization rules.
Is Theresa May's Brexit deal now dead?
Theresa May's deal cannot come into effect until it has been passed by Parliament. It has now been heavily defeated in two "meaningful" votes, and a third vote just on the withdrawal agreement itself, governing the terms of the UK's departure, not the "future relationship", a non-binding bit of the deal which maps out aspirations for long-term trade, economic and security cooperation and more. She has told EU leaders that her cross-party talks with Labour are "based on acceptance of the withdrawal agreement without reopening it" - with the aim of getting it - and a "shared vision for the future relationship", which could be subject to some change, approved by the Commons. So she has not ruled out having another go at getting it ratified - and hopes that reaching out to Labour can help break the deadlock. There is a separate sticking point about whether Speaker John Bercow will allow her to bring the deal back again for another vote.
What is the backstop?
When the UK leaves the EU, the 310-mile border between Ireland and Northern Ireland will become the land border between the UK and the European Union.
Neither side wants to see a return to checkpoints, towers, customs posts or surveillance cameras at the border, in case it reignites the Troubles and disrupts the free cross-border flow of trade and people. But they can't agree on a way to do that.
The UK and EU agreed to put in place a "backstop" - a kind of safety net to ensure there is no hard border whatever the outcome of future trade talks between the UK and the EU.
The backstop agreed between the two parties would keep Northern Ireland aligned to some EU rules on things like food products and goods standards. That would prevent the need for checks on goods at the Irish border, but would require some products being brought to Northern Ireland from the rest of the UK to be subject to new checks and controls.
The backstop would also involve a temporary single customs territory, effectively keeping the whole of the UK in the EU customs union. If future trade talks broke down without a deal, the backstop would apply indefinitely. The arrangement would end only with the agreement of both the UK and the EU.
Why are so many MPs against it?
The backstop was a key sticking point for many MPs who voted down the deal. They feared it could leave Britain tied to the EU indefinitely with no say over its rules and no ability to strike trade deals with other countries.
Are there any solutions to it?
If there were an obvious solution that people agreed guaranteed no return of a hard border in Ireland it would probably have been implemented by now. Possible alternatives suggested include a "trusted trader" scheme to avoid physical checks on goods flowing through the border, "mutual recognition" of rules with the EU and "technological" solutions. However the EU has insisted that the backstop plan is necessary.
Where does Theresa May stand on Brexit?
Theresa May was against Brexit during the referendum campaign but is now in favour of it because she says it is what the British people want. She triggered the two year process of leaving the EU on 29 March, 2017. She set out her negotiating goals in a letter to the EU council president Donald Tusk. She outlined her plans for a transition period after Brexit in a big speech in Florence, Italy. She then set out her thinking on the kind of trading relationship the UK wants with the EU, in a speech in March 2018.
Is she safe as prime minister?
Theresa May has been in a precarious position because she lost her House of Commons majority in the 2017 general election. She has survived two attempts to remove her from office so far. The first, in December 2018, was from a group of her own MPs unhappy at her Brexit policy, who organised a no confidence vote in her as Conservative leader. She survived by 200 votes to 117. She is now immune from another attempt to oust her as Tory leader until December 2019.
The second was from the Labour Party, who held a no confidence vote in her government after her Brexit plan was voted down in January 2019. All MPs were able to take part in this and she survived by 19 votes. Unlike the internal Tory no confidence vote, there is no limit to the number of times she could face a confidence vote in Parliament and Labour have not ruled out holding further ones.
However Mrs May herself has told Tory MPs she will resign, if MPs back her deal, so someone else can lead the next phase of Brexit negotiations, so her time in the top job is limited.
What is the Labour Party's position on Brexit?
Labour says it accepts the referendum result and that Brexit is going to happen. But it opposes Theresa May's Brexit plan, and wants to stop it and force a general election. In February, it said it was prepared to back another referendum to prevent a "damaging Tory Brexit", after failing to win a vote of no-confidence against the government. This is the policy the party's governing body has agreed to put in the party's manifesto for May's scheduled elections to the European Parliament. The party leadership has resisted the idea of supporting another referendum in all circumstances - as supported by deputy leader Tom Watson and a number of its MPs.
Leader Jeremy Corbyn says he would negotiate a permanent customs union with the EU after Brexit, which would be very similar to the one it has now. This is the only way to keep trade flowing freely and protect jobs, he says, as well as ensuring there is no return to a "hard border" in Northern Ireland. He has ruled out staying a member of the single market, as some of his pro-EU MPs want, so he can carry out his plans to nationalise key industries without being hampered by EU competition rules. He says the UK should have a very close relationship with the single market. Labour accepts that some form of free movement of people might have to continue.
IF THERE IS A DEAL WITH THE EU
What happens to EU citizens living in the UK and UK citizens in the EU?
An agreement between the UK and the EU provides what Theresa May says is certainty to the 3.2 million EU citizens in the UK - as well as citizens of Iceland, Liechtenstein, Norway and Switzerland that they will be able to carry on living and working in the UK as they have done with their rights enshrined in UK law and enforced by British courts. UK citizens in the EU will also retain their current rights with what the EU's Jean-Claude Juncker called a cheap and simple administration procedure.
The proposal provides a cut-off date of Brexit day - 29 March 2019 - for those to be covered by the rules. Babies born after that date to people who have qualified under these rules will be included in the agreement. Under the plan EU citizens legally resident in the UK and UK citizens in the EU will be able to leave for up to five years before losing the rights they will have as part of the proposed Brexit deal.
How will EU citizens apply for the new status?
The UK government is launching an online system to allow EU citizens to apply for settled status on 30 March. The government had originally planned to charge people £65 to use it but that fee has now been dropped and it is free. Anyone who had already paid, when the scheme was being tested, will be reimbursed.
What about EU nationals who want to work in the UK?
Any EU citizen already living and working in the UK will be able to carry on working and living in the UK after Brexit. The current plan is that even after Brexit, people from the EU will be able to move to work in the UK during a "transition" phase of about two years. There is also some debate over whether they will have the same rights as those who came before, with possible restrictions on access to benefits or to vote in local elections. The EU wants them to have the same rights as now - the UK doesn't.
What exactly happens after the transition period has yet to be decided, but the proposal is for a work permit system along the lines of that for non-EU nationals (see below).
Will immigration be cut?
Prime Minister Theresa May said one of the main messages she took from the Leave vote was that the British people wanted to see a reduction in immigration. She has insisted the UK government remains committed to reducing annual net migration - the difference between the number of people entering and leaving - to below 100,000.
Home Secretary Sajid Javid has declined to commit to this, however. Instead, he has said it will be brought down to "sustainable" levels. Mr Javid published the government's long-awaited post-Brexit immigration plans in December.
Free movement of people from the EU will effectively continue until the end of the transition period in December 2020. After that, people from the EU will need visas to work in the UK, with priority given to skilled workers - the same system that currently applies to migrants from outside the EU.
A consultation is being held on a minimum salary requirement of £30,000 for skilled migrants seeking five-year visas.
However, tens of thousands of low-skilled migrants could come to the UK to work for up to a year to protect parts of the economy that rely on overseas labour. That measure would last until 2025. Visitors from the EU will not need visas. More details here.
Will I need a visa to travel to the EU?
No. Under the Brexit deal, EU citizens and UK nationals will continue to be able to travel freely with a passport or identity card until the end of the transition period in December 2020.
After this period ends, the European Commission has offered visa-free travel for UK nationals coming to the EU for a short stay, as long as the UK offers the same in return.
British citizens will, however, have to pay €7 (£6.30) every three years to travel to EU countries, because of a new security system for countries in the passport-free Schengen zone.
Will I still be able to use my passport?
Yes. It is a British document - there is no such thing as an EU passport, so your passport will stay the same. The government has decided to change the colour to blue for anyone applying for a new or replacement British passport from October 2019.
Could the transition period be extended?
If no trade deal is in prospect by July 2020, the two sides could agree to extend the transition period instead. This would avoid the need for the backstop at that time, and keep trade with the EU flowing as it does now.
They could do this only once. The transition could not go on being extended indefinitely.
But there is no agreement on how long any extension would be. Some have suggested the end of 2022, but the government position has been for it all to be sorted before the next election, which is due in Spring 2022.
Either way, this could keep the UK under EU rules for at least three years after March's official Brexit date, something Brexiteers are also unhappy about.
IF THERE IS A NO-DEAL BREXIT
Will EU nationals have to leave the UK?
Mrs May has said EU citizens in the UK will be able to stay even if there is no deal done on Brexit. It's worth saying that even if no Brexit deal was done, EU nationals with a right to permanent residence, which is granted after they have lived in the UK for five years, should not see their rights affected after Brexit.
What about Brits living in EU countries?
There is uncertainty about what no deal would mean for Britons living in France, Spain, Germany and elsewhere. The priority for most will be to register as residents, but the rules - including deadlines for paperwork - vary from country to country. More details here.
Will I need a visa to travel to the EU?
If the UK leaves without a deal, British citizens who travel to the EU for up to 90 days will not have to apply for a visa - as long as the UK grants reciprocal visa-free travel for all EU citizens in return.
The law confirming this arrangement has been adopted by the European Parliament, and now awaits the final sign-off from EU countries. It would come into force whenever the UK leaves the EU, regardless of whether a withdrawal agreement is reached.
In the longer term, the EU is planning to launch an electronic application form, called ETIAS (European Travel Information and Authorisation System), for many non-EU countries, including the UK. It would involve paying a fee of €7 (£6.30) every three years. More details here
What about healthcare rights?
No deal would mean the current reciprocal healthcare, shared by the UK and the EU27, would no longer apply. It could send health insurance premiums soaring for UK citizens who need sufficient cover for holidays or work in the EU. Britons could also find their European Health Insurance Card (EHIC) - a passport to emergency medical treatment - is no longer valid in some EU countries. Read more here
What's going to happen to all the EU laws in force in the UK?
All existing EU laws will be copied across into UK law, to prevent legislative "black holes", under the terms of the European Union (Withdrawal Bill). The UK government can then decide over a period of time which ones it wants to keep, change or ditch.
SOME KEY BREXIT QUESTIONS
Will the UK be able to rejoin the EU in the future?
BBC Europe editor Katya Adler says the UK would have to start from scratch with no rebate, and enter 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. 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.
Has immigration come down since the UK voted to leave the EU?
According to the latest figures from the Office of National Statistics, net migration to the UK from non-EU countries was 261,000 in the twelve months to September 2018 - the highest since 2004.
By contrast, net migration from EU countries was 57,000 - a level last seen in 2009.
In other words, the result of the referendum appears to have already had an impact before Brexit has actually happened.
How much has Brexit cost so far and how much will it cost by the end?
There is much debate about the long-term costs and benefits to the UK economy of Brexit - but what we do know for certain is that the EU wants the UK to settle any outstanding bills before it leaves.
The £39bn "divorce bill" will cover things like pension payments to EU officials, the cost of relocating London-based EU agencies and outstanding EU budget commitments.
But the calculation of an exact UK share will depend on exchange rates, on interest rates, on the number of financial commitments that never turn into payments, and more. The UK says that if there is no deal agreed on Brexit it would pay substantially less and focus only on its "strict international legal obligations".
Why pay anything?
The UK could leave without any Brexit "divorce bill" deal but that would probably mean everyone ending up in court battles. If compromise can be achieved, and if payment of the bill were to be spread over many years, the amounts involved may not be that significant economically.
Will the EU still use English?
Yes, says BBC Europe editor Katya Adler. There will 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.
Will 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.
Will cars need new number plates?
If there is a no-deal Brexit, drivers may need a GB sticker if they are travelling to an EU member state, even if their car has a Euro-plate (a number plate displaying both the EU flag and a GB sign).
You will not need a GB sticker to drive outside the UK if you replace a Euro-plate with a number plate that features the GB sign without the EU flag, the Department for Transport says.
What has happened to the UK economy since the Brexit vote?
David Cameron, his Chancellor George Osborne and many other senior figures who wanted to stay in the EU predicted an immediate economic crisis if the UK voted to leave and it is true that the pound slumped the day after the referendum - and is currently about 10% down against the dollar, and 10%-15% down against the euro. Predictions of immediate doom were wrong, with the UK economy estimated to have grown 1.8% in 2016, second only to Germany's 1.9% among the world's G7 leading industrialised nations. The UK economy continued to grow at almost the same rate in 2017 but slowed to 1.4% in 2018, the slowest rate since 2012. In the first quarter of 2019, the UK economy grew at 0.5%.
Inflation rose after June 2016, reaching a five-year high of 3.1% in November 2017. However it has since eased, to stand at 1.8%. Unemployment has continued to fall, to stand at a 43-year year low of 3.9%. Annual house price increases have steadily fallen from 8.2% in June 2016 to 0.6% in the year to February 2019, according to official ONS figures.
What does the fall in the value of the pound mean for prices in the shops?
People travelling overseas from the UK since the Brexit vote have found their pound buys less.
A fall in the pound means exports get a boost as UK goods will be cheaper to buy in other countries, but some imported goods could get more expensive. The UK inflation figure for the year to December 2018 was 2%, above the target level, but not out of kilter with recent years.
Has Brexit made house prices fall?
The average price for property continued to increase after June 2016's EU referendum, although the annual growth rate slowed from 8.2% in the year to June 2016 to 0.6% in the year to February 2019, according to official ONS figures. However, the exact extent to which this is solely due to Brexit is hard to determine.
How will pensions, savings, investments and mortgages be affected?
State pensions are set to continue increasing by at least the level of earnings, inflation or 2.5% every year - whichever is the highest, no matter what happens in the Brexit negotiations.
There was an early post-referendum cut in interest rates, which has helped keep mortgage and other borrowing rates low. The reasonably strong performance of the UK economy, and the increase in inflation led to the Bank of England raising interest rates from 0.25% to 0.5% in November 2017 - the first increase in interest rates for 10 years - and then to 0.75% in August 2018. Interest rates going up generally makes it more expensive to pay back a mortgage or loan - but should be good news for savers as they should get amore interest on their money.
Will duty-free sales on Europe journeys return?
There will be no immediate return of duty-free sales if the UK leaves the EU with a version of Theresa May's deal. That's because existing customs rules will continue to apply for the planned 21-month transition period. The possible return of duty-free could be part of negotiations on a future trade deal after December 2020. If the UK leaves without a deal, duty-free sales could return.
Will leaving the EU mean the UK doesn't have to abide by the European Court of Human Rights?
The European Court of Human Rights (ECHR) in Strasbourg 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 will not exempt the UK from its decisions.
The Conservatives are committed to sticking with the Human Rights Act which requires UK courts to treat the ECHR as setting legal precedents for the UK during the Brexit process.
What about the European Court of Justice?
The Court of Justice of the European Union - to give it its full name - is the EU's highest legal authority. It is based in Luxembourg. It is an entirely different thing to the European Court of Human Rights (ECHR).
It is the European Court of Human Rights, not the ECJ that has often upset British politicians by making it harder, for example, to deport terrorist suspects. The ECJ interprets and enforces the rules of the single market, settling disputes between member countries over issues like free movement and trade. It is at the centre of pretty much everything the EU does and it having the power over UK actions has been a key issue for those arguing for the UK to leave to the EU to regain full sovereignty.
Prime Minister Theresa May has vowed that Britain will not be under the "direct" jurisdiction of the ECJ after Brexit. But she has suggested that elements of relations could - where the UK signs up to specific EU agencies - still be covered by the ECJ after Brexit
After that, there will need to be a new mechanism for settling disputes between the UK and the EU but what form that take has yet to be decided. There has been talk of an ombudsman, or some other third party, being appointed to settle disagreements.
The version of the Brexit deal, published on 8 December 2017, do also give limited powers to the ECJ in terms of EU citizens living in the UK for up to eight years. The political declaration document makes clear that ECJ will continue to have a role on interpreting EU law after Brexit.
What do 'soft' and 'hard' Brexit mean?
These terms are used during debate on the terms of the UK's departure from the EU. There is no strict definition of either, but they are used to refer to the closeness of the UK's relationship with the EU post-Brexit.
So at one extreme, "hard" Brexit could involve the UK refusing to compromise on issues like the free movement of people even if it meant leaving the single market or having to give up hopes of aspects of free trade arrangements. At the other end of the scale, a "soft" Brexit might follow a similar path to Norway, which is a member of the single market and has to accept the free movement of people as a result of that.
What is the single market?
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.
What's the difference between the single market and the customs union?
The customs union ensures EU member states all charge the same import duties to countries outside the EU. It allows member states to trade freely with each other, without burdensome customs checks at borders, but it limits their freedom to strike their own trade deals.
It is different from a free trade area. In a free trade area no tariffs, taxes or quotas are charged on goods and services moving within the area but members are free to strike their own external trade deals.
The government says the UK is leaving the customs union after the transition period but ministers have yet to decide on what will replace it.
What is Article 50?
Article 50 is a plan for any country that wishes to exit the EU to do so. It was created as part of the Treaty of Lisbon - an agreement signed up to by all EU states which became law in 2009. Before that treaty, there was no formal mechanism for a country to leave the EU. It's pretty short - just five paragraphs
THE POLITICAL SITUATION
What changed in government after the 2016 referendum?
Britain got a new Prime Minister - Theresa May. The former home secretary took over from David Cameron, who announced he was resigning on the day he lost the referendum. She became PM without facing a full Conservative leadership contest after her key rivals from what had been the Leave side pulled out.
How did the snap 2017 election change things?
Theresa May surprised almost everyone after the 2017 Easter Bank Holiday by calling an election for 8 June (it had not been due until 2020). She said she wanted to strengthen her hand in Brexit negotiations with European leaders. She said Labour, the SNP and other opposition parties - and members of the House of Lords - would try to block and frustrate her strategy. However Mrs May did not increase her party's seats in the Commons and she ended up weakened, having to rely on support from the 10 MPs from Northern Ireland's Democratic Unionist Party. You can get more detail on the 2017 election here.
Has any other member state ever left the EU?
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 Quinn visited Greenland to find out how they did it.
What does this mean for Scotland?
Scotland's First Minister Nicola Sturgeon said in the wake of the Leave result that it was "democratically unacceptable" that Scotland faced being taken out of the EU when it voted to Remain.
She has called for an extension of the 21-month transition period to give the UK government more time to negotiate a compromise with opposition parties - and has officially asked for another referendum to be held, on the final Brexit deal.
The SNP leader wants to stay in the customs union and single market after Brexit, describing it as the "least damaging" option for the UK economy as a whole - and has thrown her weight behind the campaign for another EU referendum.
They officially started a year after the referendum, on 19 June, 2017. Here's a picture from that first session:
The UK and EU negotiating teams met face-to-face for one week each month, with a few extra sessions also thrown in ahead of EU summits. Their first tasks were trying to get an agreement on the rights of UK and EU expat citizens after Brexit, reaching a figure for the amount of money the UK will need to pay on leaving, the so-called "divorce bill", and what happens to the Northern Ireland border. A provisional deal on these issues was reached on 8 December, 2017: 'Breakthrough' deal in Brexit talks. They then agreed terms for the "transition" phase and now have moved on to the permanent post-Brexit relationship, while trying to agree on the precise wording of the divorce issues.
Who has been negotiating Britain's exit from the EU?
Theresa May set up a government department, headed by veteran Conservative MP and Leave campaigner David Davis, to take responsibility for Brexit talks. Former defence secretary, Liam Fox, who also campaigned to leave the EU, was given the new job of international trade secretary and Boris Johnson, who was a leader of the official Leave campaign, was foreign secretary. These three were each playing roles in negotiations with the EU. However that has all changed now, with Boris Johnson and David Davis resigning over Theresa May's preferred Brexit plan. Dominic Raab took over as Brexit secretary - but resigned in November - and Jeremy Hunt is foreign secretary. Mrs May has made clear that she is in charge of the negotiations and the new Brexit Secretary Steve Barclay will not be getting heavily involved in the Brussels talks. Senior civil servant Olly Robbins has been the top EU official at the Brexit talks in Brussels. He started out at the top official at the Brexit department but was moved to the Cabinet Office to work directly for Theresa May, as the PM took more control over the process.
THE REFERENDUM CAMPAIGN
Who wanted the UK to leave the EU?
The UK Independence Party, which received nearly four million votes - 13% of those cast - in the 2015 general election, but who saw their vote collapse to about a quarter of that at this year's election, has campaigned for many years for Britain's exit from the EU. They were joined in their call during the referendum campaign by about half the Conservative Party's MPs, including Boris Johnson and five members of the then Cabinet. A handful of Labour MPs and Northern Ireland party the DUP were also in favour of leaving.
What were their reasons for wanting the UK to leave?
They said Britain was being held back by the EU, which they said imposed too many rules on business and charged billions of pounds a year in membership fees for little in return. They also wanted the UK to make all of its own laws again, rather than being created through shared decision making with other EU nations.
Immigration was also a big issue for Brexit supporters, they wanted 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. The Leave campaign also objected to the idea of "ever closer union" between EU member states and what they see as moves towards the creation of a "United States of Europe".
Who wanted the UK to stay in the EU?
Then Prime Minister David Cameron was the leading voice in the Remain campaign, after reaching an agreement with other European Union leaders that would have changed the terms of Britain's membership had the country voted to stay in.
He said the deal would give Britain "special" status and help sort out some of the things British people said they didn't like about the EU, like high levels of immigration - but critics said the deal would make little difference.
Sixteen members of Mr Cameron's Cabinet, including the woman who would replace him as PM, Theresa May, also backed staying in. The Conservative Party was split on the issue and officially remained neutral in the campaign. The Labour Party, Scottish National Party, Plaid Cymru, the Green Party and the Liberal Democrats were all in favour of staying in.
The then US president Barack Obama also wanted Britain to remain in the EU - unlike his successor, Donald Trump, who is an enthusiastic champion of Brexit - as did the leaders of other EU nations such as France and Germany.
What were their reasons for wanting the UK to stay?
Those campaigning for Britain to stay in the EU said it got a big boost from membership - it makes selling things to other EU countries easier and, they argued, the flow of immigrants, most of whom are young and keen to work, fuels economic growth and helps pay for public services.
They also said 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.
What about businesses?
Big business - with a few exceptions - tended 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.
Given the crucial role of London as a financial centre, there's interest in how many jobs may be lost to other hubs in the EU. Some UK exporters say they've had increased orders or enquiries because of the fall in the value of the pound. Others are less optimistic, fearing products for the European market may have to be made at plants in the EU.
Who led the rival sides in the referendum campaign?
The main cross-party group campaigning for Britain to remain in the EU was headed by former Marks and Spencer chairman Lord Rose. It was 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 ran 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 funded the campaign: Britain Stronger in Europe raised £12.1m, including 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).
Who else campaigned to remain: The SNP ran its own remain campaign in Scotland as it did not want to share a platform with the Conservatives. Several smaller groups also registered to campaign.
A cross-party campaign that had 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 were also involved. It had 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 funded the campaign: Vote Leave raised £9.8m. Among its supporters was 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.
Who else campaigned to leave: UKIP leader Nigel Farage was not part of Vote Leave. His party ran its own campaign and was involved in Leave.EU, a campaign run by former UKIP donor Arron Banks, which raised a total of £3.2m. The Trade Union and Socialist Coalition also ran its own out campaign. Several smaller groups also registered to campaign.
Here are a selection of questions sent in - you can ask yours via the form at the end of this page
Which MPs were for staying and which 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.
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.
What will happen to protected species?
Dee, from Launceston, wanted to know what would happen to EU laws covering protected species such as bats in the event of Britain leaving the EU.
As already mentioned the plan is for all EU laws to be transferred into UK law as part of the EU (withdrawal) Bill. That means the government then has time to decide what laws to keep, scrap or change without the risk of a legal black hole on the first day after Brexit.
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 issue has been a hot one and Environment Secretary Michael Gove has insisted that the UK will maintain or enhance its environmental laws.
Will we 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: "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."
What will happen to pet passports?
The answer to Alan's question, the European Commission says, is that pet passports will, like everything else, depend on whether the UK leaves with a deal or not.
The UK introduced the pet passport scheme in 2000, replacing the previous quarantine laws. It means you and your dog, cat or ferret can travel between the UK and the EU (and other participating countries) as long as it has a passport, a microchip and has been vaccinated against rabies.
If the UK leaves with a deal, this will not change.
If there's no deal, pet passports issued in the UK would not be valid for travel to the EU.
Pet owners planning to travel with their animals, would need to get them microchipped and vaccinated against rabies. Further details are on the government website.
What is the 'red tape' that opponents of the EU complain 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.
Most of the EU-derived laws on the UK's statute books will be copied across into UK law so that businesses can continue to function on the day Britain leaves the EU, in March 2019. Future governments will then be able to amend or scrap them.
Brexit may also generate "red tape" of its own - if the UK leaves the single market and the customs union, businesses could face more paperwork as they cross borders into EU countries.
Will Britain be party to the Transatlantic Trade and Investment Partnership?
Ste, in Bolton, asked about this. The Transatlantic Trade and Investment Partnership - or TTIP - currently under negotiation between the EU and United States would create the biggest free trade area the world has ever seen.
Cheerleaders for TTIP, including former PM David Cameron, believed 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, feared it would shift more power to multinational corporations, undermine public services, wreck food standards and threaten basic rights.
This debate now appears academic as US President Donald Trump is not a fan of the agreement, which means it has been shelved in its previous form - but whatever happens, when the UK quits the EU it would no longer be part of a revived TTIP and is planning to negotiate its own trade deal with the US.
What impact will leaving the EU have on the NHS?
Paddy, from Widnes, wanted to know how leaving the EU will affect the number of doctors we have and 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 claimed was £350m a week, could be spent on the NHS instead. The BBC's Reality Check team looked into this claim.
Before the vote the then Health Secretary Jeremy Hunt 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 insisted that EU membership fees could be spent on domestic services like the NHS.
Since the referendum there has been a relaxation of the immigration rules for doctors from outside the EU and an increase in the planned number of "home grown" doctors qualifying through new medical schools. But according to Personnel Today there were fewer EU nationals moving to work in the NHS, and an increase in the number quitting.
Spending on the NHS has continued at the same level as planned before the referendum, although Theresa May said in June 2018 that a "Brexit dividend" was helping fund a larger-than-planned £20bn increase in NHS spending in England by 2023.
Adrian runs a small electronics company and wants to know about export tariffs after Brexit
As long as Britain has been in the EU we haven't really talked much about tariffs. That's because all trade within the European Economic Area is tariff-free. On top of that the EU has trade agreements with 52 other countries as well.
After Brexit, Britain is going to have to negotiate new deals all on its own. That's both a problem and an opportunity.
For example you can use tariffs against foreign imports to protect businesses you care about, as the EU does with agricultural produce, but you do then run the risk of retaliation from your trading partners.
The key body in all of this is the World Trade Organisation and at the moment the UK is only a member via its membership of the EU.
The UK will automatically become a member in its own right as soon as it leaves the EU.
The principle of non-discrimination means that WTO members must not treat any member less advantageously than any other.
In practice, this should prevent the EU introducing tariffs on the UK which would discriminate against us, or the UK introducing similar tariffs on the EU.
Non-food items imported into the EU currently have a tariff of about 2,3%. Cars have a 10% tariff - but if the EU were to impose a 10% tariff on UK car imports, then the UK could impose the same tariff on German and French cars. The two sides would want to avoid a tit-for-tat trade war.
They are hoping to strike a broad agreement on trading terms by December 2020, which would include a "free trade area and deep co-operation on goods, with zero tariffs and quotas".
The UK will also need to reach agreements with other nations around the world.
What impact will leaving have on the UK's long term political influence in Europe
In reply to Peter - there are basically two views on what will happen in terms of clout when outside the EU.
View one is that the UK projects power and influence in the world, working through organisations such as the EU and that on our own it'll be a much diminished force.
View two is that unencumbered by the other 27 members, the UK can get on with things and start adopting a much more independent, self-confident, assertive role on the world stage.
How will access to healthcare change for expats living in the EU
Veronique, who lives in Italy asked this one. After Brexit, there will be two possibilities.
If the UK leaves the EU without a deal, the situation will depend on the individual country where you live.
For the Bradleys in Italy, for example, residents from non-EU countries, and that will soon include the Brits, will have to finalise their residency status, acquire an Italian identity card and then apply for an Italian health insurance card.
If they visit the UK at the moment, access to the NHS for non-resident Brits is not straightforward unless you have a European health insurance card.
The right to treatment is based on residency, not on your tax status.
So, even if you live abroad and pay some British tax on a buy-to-let property for instance, you might find yourself getting a bill for any NHS treatment you end up getting while you are back in the UK.
What will happen to EU nationals with a British state pension
Peter, a German citizen living in the UK asked this question, and the good news is that if you are an EU national and you get a British state pension, nothing much should change, because the state pension is dependent not on where you come from, but on how long you have paid National Insurance contributions in the UK.
So it doesn't matter whether you come from Lithuania or Latvia or Transylvania or Timbuktu, what counts is how much you have paid in terms of National Insurance contributions.
There is one wrinkle though and that is that you have to have paid in for at least 10 years.
Under the current rules, if you are an EU citizen and haven't paid in for 10 years, you can point to any contributions you have made in your native country and say, "I paid in there", and that will count.
That works for EU countries and another 16 countries with which the UK has social security agreements.
Once we have left the EU, you will no longer be able to do that unless we negotiate new reciprocal agreements.
If we don't then potentially, if you have paid in fewer than than 10 years' worth of National Insurance contributions, you will not get a British state pension.
Is it possible to be both an EU citizen and not an EU citizen
Anyone born in Northern Ireland has an absolute right to carry both passports.
Declan, an Irish passport holder, might be happy to know that this is one of the few questions where I can't see a downside as long as you are happy and comfortable carrying both passports.
The Irish document means you continue to enjoy the benefits of EU citizenship, and the British passport will give you full rights in the UK at the same time.
Call it one of the clear joys of coming from Northern Ireland, alongside the rolling hills, rugged coastline and enjoyable breaks between the showers.
All you have to do is remember to carry the Irish passport when you are joining the EU citizens-only queue at the airport in future.