Here is an easy-to-understand guide to Brexit - beginning with the basics, then a look at the negotiations, followed by a selection of answers to questions we've been sent.
What's happening now?
The fifth round of monthly Brexit talks between the UK and the EU has taken place, with a decision due to be taken by the EU later in October on whether or not enough progress has been made on "separation issues" to be able to start talks about the future relationship between the UK and the EU after Brexit. Theresa May tried to speed up progress with a speech in Florence, Italy, in which she called for trade with the EU to continues as it is for two years after Britain leaves, but EU figures say not enough progress has been made yet. EU negotiator Michel Barnier has said it could be "weeks or months" before the talks move on to the next stage.
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 possible Greek exit from the euro was dubbed Grexit in the past.
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 changed in government after the referendum?
David Cameron leaves No 10, Theresa May enters No 10Image copyrightPA
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. Like Mr Cameron, Mrs May was against Britain leaving the EU but she played only a very low-key role in the campaign and was never seen as much of an enthusiast for the EU. She became PM without facing a full Conservative leadership contest after her key rivals from what had been the Leave side pulled out.
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. Her key message has been that "Brexit means Brexit" and she triggered the two year process of leaving the EU on 29 March. 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.
How did the snap election change things?
Theresa May surprised everyone after the 2017 Easter Bank Holiday by calling an election for 8 June (it had been due in 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.
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 remains around 10% lower against the dollar and 15% down against the euro.
But 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. UK growth has slowed so far in 2017, but the economy is still expanding. Inflation has risen since June 2016 to stand at 2.6%, but unemployment has continued to fall, to stand at a 42 year low of 4.4%. Annual house price increases have fallen from 9.4% in June 2016 but were still at an inflation-beating 4.7% in the year to May 2017, according to official ONS figures.
Brexit talks are under way
They finally, officially, started on 19 June, 2017. Here's a picture from that first session:
The UK and EU negotiating teams are scheduled to meet face-to-face for one week each month. Their first tasks are trying to get an agreement on the rights of UK and EU 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. You can find out more about the talks here.
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 such as mobile phone charges. Click here for a beginners' guide to how the EU works.
What is Article 50?
Article 50 is a plan for any country that wishes to exit the EU. 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 - which spell out that any EU member state may decide to quit the EU, that it must notify the European Council and negotiate its withdrawal with the EU, that there are two years to reach an agreement - unless everyone agrees to extend it - and that the exiting state cannot take part in EU internal discussions about its departure.
What date will the UK will leave the EU?
For the UK to leave the EU it had to invoke Article 50 of the Lisbon Treaty which gives the two sides two years to agree the terms of the split. Theresa May triggered this process on 29 March, meaning the UK is scheduled to leave on Friday, 29 March 2019. It can be extended if all 28 EU members agree, but at the moment all sides are focusing on that date as being the key one.
What's going to happen to all the EU laws in force in the UK?
The Conservative government has introduced the European Union (Withdrawal) Bill to Parliament. If passed, it will end the primacy of EU law in the UK. This "Great Repeal Bill" as it has been called, is supposed to incorporate all EU legislation into UK law in one lump, after which the government will decide over a period of time which parts to keep, change or remove. The government is facing claims from Remain supporting MPs that it is giving itself sweeping powers to change legislation without proper Parliamentary scrutiny. Read a full guide to the bill.
What is the Labour Party's position on Brexit?
Labour's position on Brexit was tweaked in mid-August, when the shadow Brexit secretary, Sir Keir Starmer, announced that the party now wanted to keep the UK in the single market and a customs union during a transition that could last for up to four years.
Labour would also accept free movement of people, payments into the EU budget and the jurisdiction of the European Court of Justice during the transition. This is a considerably "softer" version of Brexit than the one advocated by the government, but there are still divisions within the party about whether the UK should try to stay in the single market in the longer term.
What do 'soft' and 'hard' Brexit mean?
These terms have increasingly been used as debate focused 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 meant leaving the single market. 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. Theresa May has ruled out the UK staying in the single market. Labour leader Jeremy Corbyn has said continued membership of the single has to be an option in negotiations with Brussels. Read more: A free trade area v EU single market
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 single market is a very different beast - it is not just about the trade in goods. It allows the free movement of people, money and services as if the EU was a single country.
Who is 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. 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, is foreign secretary. These three are each set to play roles in negotiations with the EU and seek out new international agreements, although it would be Mrs May, as prime minister, who would have the final say. Who's who guide to both sides' negotiators.
How long will it take for Britain to leave the EU?
The Article 50 process lasts two years so the intention is for the UK to leave the EU on 29 March 2019. EU law still stands in the UK until it ceases being a member. But there is currently uncertainty about how final the break will be on that day - a number of UK and EU figures back the idea of having a "transition" period of up to three years to allow a smooth implementation of whatever Brexit deal is negotiated and minimise disruption to businesses and holidaymakers etc.
Why might Brexit take so long?
Unpicking 43 years of treaties and agreements covering thousands of different subjects was never going to be a straightforward task. It is further complicated by the fact that it has never been done before and negotiators will, to some extent, be making it up as they go along. The post-Brexit trade deal is likely to be the most complex part of the negotiation because it needs the unanimous approval of more than 30 national and regional parliaments across Europe, some of whom may want to hold referendums.
So why can't the UK just cut all ties in March 2019?
The UK could cut all ties, but Theresa May and others would like to avoid such a "cliff-edge" where current regulations on things like cross-border trade and travel between the UK and the EU ends overnight. They think it would harm the economy.
What is the focus of negotiations between the UK and EU?
The priority issues in negotiations are:
1) Agreeing what rights EU citizens already in the UK - and UK citizens living in the rest of the EU - will have after Brexit.
2) Agreeing a figure for the amount of money the UK has to pay the rest of the EU "to settle its accounts", when it leaves.
3) Working out what will happen on the border between Northern Ireland, when it is outside the EU, and the Republic of Ireland, which is part of the EU.
The EU says it wants to make decent progress on these three issues before beginning talks about what the UK's relations with the EU will be like after Brexit. Mrs May set out her negotiating priorities in the letter officially triggering the process of leaving the EU on 29 March. Here's a guide to the key points.
How are the talks going?
There have been agreements on some technical points, but the chief EU negotiator, Michel Barnier, has said there had been no decisive progress on any of the main issues. The UK's Brexit Secretary, David Davis, insists progress has been made. The main sticking point at the moment is money - and the size of the bill the UK will pay to cover its outstanding obligations when it leaves.
The UK wants this to be as low as possible. All the other countries in the EU want it to be as high as possible. Because when the UK leaves, there will be a hole in the EU budget and they will have to cover the shortfall. The UK government has published a series of papers setting out its position on issues such as future customs arrangements, and on the border between Northern Ireland and the Republic of Ireland.
Government policy is now that the UK will leave the single market and the customs union on the day of Brexit, but that it will try to replicate existing customs arrangements during a time-limited transition period.
What happens if there is no deal with the EU?
Prime Minister Theresa May says leaving the EU with no deal whatsoever would be better than signing the UK up to a bad one. Without an agreement on trade, the UK would have to operate under World Trade Organisation rules, which could mean customs checks and tariffs on goods as well as longer border check for travellers.
There are also questions about what would happen to Britain's position as global financial centre and the land border between the UK and the Republic of Ireland. There is also concern that Brits living abroad in the EU could lose residency rights and access to free emergency health care. Here is a full explanation of what 'no deal' could mean
What happens to EU citizens living in the UK?
It has yet to be agreed. All EU nationals lawfully resident in the UK for at least five years will be able to apply for "settled status" and be able to bring over spouses and children, under a 15-page proposal unveiled by Theresa May. Mrs May says she wants to give reassurance and certainty to the 3.2 million EU citizens in the UK - as well as citizens of the three EEA countries and Switzerland.
But any deal on their future legal status and rights must be reciprocal and also give certainty to the 1.2 million British expats living on the continent after the UK leaves the EU - expected to be on 29 March 2019, she says.
Michel Barnier, who is leading the Brexit negotiations for the EU, said the UK's proposals did not go far enough and he wanted the same level of protection citizens currently have under EU law. He has demanded more clarity and ambition from the UK government.
The key points of the UK's proposals are:
Those granted settled status will be able to live, work, study and claim benefits just as they can now
The cut-off date for eligibility is undecided but will be between 29 March 2017 and 29 March 2019
Family members of EU citizens living abroad will be able to return and apply for settled status
EU nationals in the UK for less than five years at the specified date will be able to continue living and working in the UK
Once resident for five years, they can apply for settled status
Those arriving after the cut-off point will be able to stay temporarily
But there should be "no expectation" they will be granted permanent residence
A period of "blanket residence permission" may apply to give officials time to process applications to stay in the UK
The Home Office will no longer require evidence that EU citizens who weren't working held "comprehensive sickness insurance"
Labour has said it would guarantee the rights of of EU citizens living in the UK to stay there on "day one" of a Labour government.
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 happens to UK citizens working in the EU?
A lot depends on the kind of deal the UK agrees with the EU. If the government opted to impose work permit restrictions on EU nationals, 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
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 up to three years. However they will have to register. A permanent proposal for post-Brexit immigration is not likely to be known for a few months yet, although it is widely expected that there will be a work permit system along the lines of that for non-EU nationals.
What does the fall in the value of the pound mean for prices in the shops?
Media captionShoppers will need to keep a close eye on how much they are spending
People travelling overseas from the UK have found their pounds are buying fewer euros or dollars after the Brexit vote. Even if the pound regains some of its value, currency experts expect it in the longer term to remain at least 10% below where it was when the referendum happened.
This means exports should get a boost as UK goods will be cheaper, but imported goods will get more expensive - some price rises for food, clothing and homeware goods have been seen. The latest UK inflation figures have the rate at 2.6%, above the target level, but not out of kilter with recent years.
Will immigration be cut?
Prime Minister Theresa May has said one of the main messages she has taken from the Leave vote is that the British people want to see a reduction in immigration. She has said this will be a focus of Brexit negotiations as she remains committed to getting net migration - the difference between the numbers entering and leaving the country - down to a "sustainable" level, which she defines as being below 100,000 a year.
The rate of increase in the size of Britain's population has slowed significantly since the Brexit vote. This has largely been driven by an increase in emigration from the UK by citizens of Poland and the other East and Central European countries. There were still 246,000 more people coming to live in the UK than leaving in the year to March 2017, according to the latest estimates - some way above the government's target of 100,000.
Could there be a second referendum?
It seems highly unlikely. Both the Conservatives and the Labour Party have ruled out another referendum, arguing that it would be an undemocratic breach of trust with the British people who clearly voted to Leave.
Will MPs get a vote on the Brexit deal?
Yes. Theresa May has promised there will be a Commons and Lords vote to approve whatever deal the UK and the rest of the EU agree at the end of the two year process. This vote is currently proposed as a "take it or leave it" one. Labour wants the vote to have the option of sending the UK team back to renegotiate. It is worth mentioning that any deal also has to be agreed by the European Parliament - with British MEPs getting a chance to vote on it there.
Will I need a visa to travel to the EU?
The UK government wants to keep visa-free travel to the UK for EU visitors after Brexit and it is hoping this will be reciprocated, meaning UK citizens will continue to be able to visit EU countries for short periods without seeking official permission to travel.
If visitors from EU countries wanted to work, study or settle in the UK they would have to apply for permission under the proposals.
No agreement has been reached yet, however. If it is decided that EU citizens will need visas to come to the UK in the future, then UK citizens will need visas to travel to the EU.
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. 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.
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. Ms Sturgeon has officially asked for permission for a second referendum to be held. She had wanted the vote to be held between the autumn of 2018 and spring 2019, but after losing seats at the 2017 general election she has put her plans on hold with no referendum likely until 2021. Theresa May has said a second referendum should not be held during the Brexit process.
What does it mean for Northern Ireland?
The land border between Northern Ireland and EU member the Republic of Ireland is a key part of the Brexit talks. There is currently a common travel area between the UK and the Republic. Like Scotland, Northern Ireland voted to remain in the EU in last year's referendum. The result in Northern Ireland was 56% for Remain and 44% for Leave.
The UK government has published a paper setting out its vision for a post-Brexit border. It wants to avoid returning to a "hard border" - that means no physical infrastructure, such as customs posts.
There would be no CCTV cameras or number plate recognition technology at the border, or set back from it. Instead, the UK government is arguing for a wide-ranging exemption under which small and medium-sized businesses will not have to comply with any new customs tariffs. If the proposals are accepted, customs officials envisage using a mix of technology and physical checks to monitor the compliance of bigger businesses engaged in international trade.
Critics say the proposals lack credible detail, with Labour deriding the plans for the border as "a fantasy frontier".
Sinn Fein, which was part of the ruling coalition in the Northern Ireland Assembly before it was suspended, has called for a referendum on leaving the UK and joining the Republic of Ireland as soon as possible. The Conservatives have rejected Sinn Fein's call, saying there was no evidence opinion had shifted in favour of a united Ireland.
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.
There have been no official estimates published of the size of the bill, which covers things like pension payments to EU officials, the cost of relocating London-based EU agencies and outstanding EU budget commitments.
Various figures ranging from 50bn (£44bn) to 100bn (£88bn) euros have been bandied about but although the UK has agreed to meet its financial obligations, Brexit secretary David Davis has said: "We will not be paying €100bn."
The UK could leave without any Brexit "divorce bill" deal but that would probably mean everyone ending up in court. 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.
How will pensions, savings, investments and mortgages be affected?
During the referendum campaign, David Cameron said the so-called "triple lock" for state pensions would be threatened by a UK exit. This is the agreement by which pensions increase by at least the level of earnings, inflation or 2.5% every year - whichever is the highest. Theresa May had proposed ditching the 2.5% part of the lock in the party's election manifesto, but as part of the post-election deal with the DUP the triple lock was again guaranteed.
There was an early post-referendum cut in interest rates, which has helped keep mortgage and other borrowing rates low. There are few signs yet that rising inflation have worried the Bank of England enough to consider raising interest rates. But if that happened it would make mortgages and loans more expensive to repay - but would be good news for savers.
Will duty-free sales on Europe journeys return?
Journalists and writers on social media have greeted the reintroduction of duty-free sales as an "upside" or "silver lining" of Brexit. As with most Brexit consequences, whether this will happen depends on how negotiations with the EU play out - whether the "customs union" agreement between Britain and the EU is ended or continued.
Will EHIC cards still be valid?
If you are already living in another EU country on the day the UK leaves the bloc, your 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 - will continue to work.
After that date, for EU citizens wishing to travel to the UK or UK citizens wishing to travel to the EU, it is unclear about what will happen because no deal has yet been reached.
Will 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.
Could MPs block an EU exit?
Could the necessary legislation pass the Commons, given that a lot of MPs in the current Parliament - all SNP and Lib Dems, nearly all Labour and many Conservatives - were in favour of staying? 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 also has 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.
So in theory they could block the UK's EU exit. But in practice that is seen as very unlikely given that a majority of people voted for Brexit in the referendum.
Will leaving the EU mean we don'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. There have been longstanding plans to repeal the act and replace it with a British Bill of Rights.
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 ECHR 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.
Prime Minister Theresa May has vowed that Britain will not be under the "direct" jurisdiction of the ECJ after Brexit. But the UK government has not ruled out remaining under its jurisdiction during the Brexit transition period that is planned after March 2019.
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 UK has set out some ideas in a position paper, which was criticised for being too "vague". The EU is insisting that its citizens in the UK should continue to enjoy the legal protection of the ECJ even after Brexit, guaranteeing their right to work and access to benefits among other things.
This is a major sticking point in the negotiations, with the UK saying EU citizens living in the UK should be subject to British law only.
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.
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, 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 campaign?
Britain Stronger in Europe - 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 £6.88m, 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 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.
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 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 £2.78m. Its largest supporter 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. Read a Who's Who guide. Who else campaigned to leave: UKIP leader Nigel Farage was not part of Vote Leave. His party ran its own campaign. The Trade Union and Socialist Coalition also ran its own out campaign. Several smaller groups also registered to campaign.
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.
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 is one of 10 member states who pay more into the EU budget than they get out
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 will happen to his retirement plans. 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.
In some other EU countries such as France expats of working age are expected to pay the same healthcare costs as locals but once they reach retirement age their medical bills are paid by the NHS.
If Britain 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.
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. The answer is that they would remain in place, initially at least. After the Leave vote, the government will 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 would have got back from the benefit curbs negotiated by David Cameron in Brussels. We don't exactly know because the details were never worked out. HM Revenue and Customs 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 would have been significantly less than that because Mr Cameron did not get the blanket ban he wanted. Instead, payments would have been linked to the cost of living in the countries where the children live. David Cameron said 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" was applied. The DWP estimated between 128,700 and 155,100 people would be affected. But the cuts would have been phased in. New arrivals would not have got tax credits and other in-work benefits straight away but would have gradually gained access to them over a four year period at a rate that had not been decided. The plan will never be implemented now.
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 Rippington's question, the European Commission says, is that pet passports will, like everything else, form part of the negotiations.
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.
Of course, until the UK actually leaves the EU, the scheme continues as normal.
The Department for Environment, Food and Rural Affairs said: "The UK has a long history of world-leading animal welfare and biosecurity standards, which we are committed to safeguarding and improving, securing the best deal for Britain as we leave the EU."
Has Brexit made house prices fall?
So far, the answer is no. But there has been anecdotal evidence of house prices falling at the top of the market in Central London and the annual increase in the price of property has fallen from 9.4% at the time of the referendum to 4.9% a year later.
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, fear it will shift more power to multinational corporations, undermine public services, wreck food standards and threaten basic rights.
US President Donald Trump is not a fan of the TTIP agreement, which means it is now seen as unlikely to be agreed - but whatever happens, when the UK quits the EU it will not be part of TTIP and will have 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 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 spending on the NHS has continued at the same level as planned. EU citizens working for the NHS are expected to get the right to stay in the UK, although details on EU citizens in the UK and UK citizens elsewhere in the EU are yet to be finalised (see earlier answer).
Sally Miller bought a house in Spain nine years ago and plans to retire there in the next five years. She asked how Brexit will affect this.
The BBC's Kevin Connolly says:
The issue of free movement - the rights of EU citizens to live and work in the UK - was a huge issue in the Brexit referendum of course, and will be a big part of the exit negotiations.
We've heard quite a bit from the British side already with the government saying that securing the status and rights of EU nationals in the UK and UK nationals in the EU is one of the government's earliest priorities, and specifically that it is looking for a reciprocal deal.
So you might feel the mood music is encouraging but all we can say for sure is that, while there are no guarantees yet, it will be a big part of the Brexit negotiations to come.
Jonathan Eaton is a Briton living in the Netherlands with his wife, who is Dutch. He asks what rights to benefits and housing he will have if he has to return to the UK.
BBC assistant political editor Norman Smith says:
The short answer is there is no easy access to benefits. As it stands at the moment, Brexit aside, you will have to pass what's known as a habitual residence test which was introduced in 1994 and applies to British citizens just as EU citizens.
The rules have been tightened up which means for some benefits, if you have been out of the country you can't even think about applying for the test for several months. For example, when it comes to jobseeker's allowance, you cannot even take the test to apply for those benefits for three months. And that was done to stop EU citizens coming here and just getting on benefits straight away.
After three months, you can take the test which looks at your English language skills, what sort of efforts you made to find work before coming to the UK. It also considers how strong a tie you have to the UK, whether you have property or family here and what your intentions are in terms of staying and working, or returning.
But once you have taken the test, if you pass it then you should be eligible to apply for a range of benefits, as long as you meet the usual requirements in terms of income and showing you are looking for work. That is likely to continue when we move fully on to Universal Credit.
The one sort of unknown in the whole system is what happens with Brexit negotiations, in terms of guaranteeing the rights of British nationals abroad.
And we simply don't know what that will involve and whether in any way that might impact on how soon you can apply for benefits when you come back to Britain.
Will I have to buy a new passport and driving licence, and will my rights to use them freely across Europe be taken away from me after Brexit, asks Francis Lee.
Kevin Connolly says:
At the moment UK passports carry the words European Union and British driving licences have the blue square with yellow flags of the EU. That will presumably change after Brexit but it seems likely that the change will be phased in so that you'll simply get documents with the new design when the old ones expire. That's what happened, I seem to remember, when the UK joined the EU. Anything else would be expensive and risk flooding the system, after all.
The right to use them freely is an interesting question. When we talk about restrictions on freedom of movement we generally mean the freedom to live and work in another country. If Britain poses restrictions on the EU in that respect then it can expect some kind of response.
But in terms of tourism there are plenty of non-EU countries whose citizens can visit the UK for up to 90 days without a visa. And, as part of the Brexit negotiations, you'd expect similar arrangements to be discussed for the UK.
Both sides need each others' tourists and, after all, if you can drive a car in the United States on a UK licence then it doesn't seem fanciful to assume that you'll be able to do the same in Europe in future.
It is very clear that the PM and the government want to leave the tyranny of the European Court of Justice. Why has leaving the European Court of Human Rights (an organisation far more hated than the ECJ) been ignored, asks Barry Fryer.
Kevin Connolly says:
Two different courts here of course, so two different bits of politics. Crucially, the European Court of Human Rights is not an EU institution and that's why discussions about leaving it have not formed a key part of the Brexit debate.
The European Court of Justice - the ECJ - is one of the primary institutions of the European Union and administers EU law. So, while it might have a role in supervising a future trade deal, part of the goal of Brexit was to remove the UK from the ECJ's jurisdiction.
The European Court of Human Rights which, as Barry points out, can be even more controversial, is a body set up not by the EU but by member states of the Council of Europe, a separate institution which contains countries that aren't EU members.
It's this court which has produced rulings which have been controversial in the UK, including blocking the extradition of Abu Qatada and establishing the right of serving prisoners to vote in elections - and leaving the EU won't change anything here.
Adrian Wallis runs a small electronics company and wants to know about export tariffs after Brexit, and what they'd mean for his business.
Kevin Connolly says:
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.
One bit of good news is that the UK will automatically become a member in its own right as soon as it leaves the EU.
That matters because in the period when the UK is negotiating a new trade deal with the EU, and that could take years, trade would be conducted under WTO rules.
At the moment, for non-food items, that implies an average tariff of about 2.3%.
But suppose the EU were to impose a 10% tariff on UK car imports, for example. Well, then the UK could impose the same tariff on German and French cars.
In theory, an economist would say that creates a situation where everyone has an incentive to sort out a better deal for their consumers.
The snag is that these things take years, if not decades. They tend to be done on a country-by-country and sector-by-sector basis.
So if Adrian is waiting to find out the implications for his business, then I'm afraid he's going to have to be patient.
Maybe very, very patient.
What impact will leaving the European Union have on the UK's long term political influence in Europe, asks Peter Hoare.
Norman Smith says:
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.
My take is that not much is probably going to change.
I say that because the UK'll still be a member of significant organisations such as the UN and Nato, and will still be co-operating with EU partners. For example, there will still be close ties on defence with the French.
The UK will still be the same old Britain, will still have significant military force, will still be a wealthy country and will still be a nuclear power, so I don't think people will suddenly think the UK's an entirely different country.
Are other countries likely to leave the EU and if so could we start a new free trade area, asks David John.
Kevin Connolly says:
Funnily enough, I was discussing this question just the other day with a French politician, a conservative and a real Europhile, and he said he thought if there was a free vote in France tomorrow, as the right wing National Front would like, that the French would vote to leave.
But generally speaking I can't see much prospect of a tidal wave of insurrectionist, exitism sweeping the continent. When a country like Ireland has a spat with the EU about tax, for example, it does annoy Irish politicians, but most mainstream leaders in the Europe have grown up with the idea that the EU has brought peace and prosperity for decades.
Lots of them see plenty that irritates them about the European Union, but they mainly argue that the benefits hugely outweigh the irritations. And in countries where you do find Euroscepticism, such as Poland and Hungary, there is also a healthy awareness that there are huge financial benefits to membership.
As for the future, we will see. If the UK were to get a fantastic Brexit deal then maybe others would be tempted to go.
But the truth is, lots of European politicians want the EU to be tough with Britain precisely to stop other countries from following it through the door.
As to Britain forming its own free trade area, I think it seems an awfully long shot and on balance it is unlikely, not least because there are not that many free countries around available to recruit into another free trade area.
Britain could perhaps join the Free Trade Association along with Norway, Lichtenstein and Switzerland. But of course it would be joining under existing rules, so the likeliest future for a post-Brexit UK, I think, is a future where it tries to do the best deal possible with the EU and then looks around for other free trade deals.
But that would fall short of creating a free trade area based on the UK itself.
What will happen to the borders in Gibraltar and Northern Ireland, asks Nigel May.
Kevin Connolly says:
I think the question of what is going to happen to borders after Brexit is one of the most difficult of the lot.
Since 1985 when Spain joined the EU, it has basically been prevented from closing the border with Gibraltar as a way of applying pressure to the British territory.
In fact, 12,000 Spanish people cross into the territory to work every day and the area of Spain around Gibraltar is a pretty depressed area so they are important jobs.
On the other hand, the Spanish have talked openly about this being an opportunity to get Gibraltar back. Jose Manuel Garcia-Margallo, its minister of foreign affairs, said in September the UK's vote to leave the EU was "a unique historical opportunity in more than three hundred years to get Gibraltar back".
But at a minimum, as things stand, it looks to me as though they could certainly re-impose border controls if they chose to.
The situation with Ireland's border is more complex.
For those of us for whom Northern Ireland is home, the total disappearance of military check points on the border is one of the most tangible daily reminders of the end of the Troubles and no one wants a border like that back.
But, when the day comes when Ireland is in the EU and the UK is not, then the Irish border of course is also going to be the UK's land border with the European Union.
Conservative leader Theresa May has said we don't see a return to the borders of the past, but the reality is that if Britain leaves the common customs area, then presumably some sort of checks are going to be necessary on that border.
And if the UK wants to stop Polish or Romanian migrant workers using Dublin airport as a back door into the UK, then it is going to have to do something about that too. The UK has published a paper setting out its preferred options.
Of course, what it will all mean for towns and villages like Belleek and Belcoo in County Fermanagh, which more or less straddle the border, is hard to imagine.
How will access to healthcare change for expats living in the EU, asks Veronique Bradley, who lives in Italy.
Kevin Connolly says:
Healthcare is one of those issues that remains relatively simple as long as the UK remains in the EU.
It is just part of a range of citizens' rights that apply across the entire union. After Brexit, I suppose there will be two possibilities.
The first and easiest would be that the negotiators come up with a reciprocal deal that keeps the current arrangements, or something a bit like them, in place.
If they don't, 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 who lived and worked in the UK and now receive a British state pension, asks Peter Barz, a German citizen living in the UK.
Norman Smith says:
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, asks Declan O'Neill, who holds an Irish passport.
Kevin Connolly says:
I should probably declare some sort of interest here as a dual Irish and British national myself.
Of course, anyone born in Northern Ireland has an absolute right to carry both passports.
Declan 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.
Is there a get-out clause for Article 50, asks Gillian Coates.
Norman Smith says:
I think the honest answer is you would have to be a legal eagle to answer this.
But my take on it is that legally it looks like once we trigger Article 50 we are locked in, and that is certainly how the European Parliament reads it.
And there is a view that if we were in this two-year process after triggering Article 50 and we wanted to get out of it, then ultimately that would be a decision for the European Court of Justice.
However, in the real world I think it is likely to be rather different, whatever the legal protocol.
I think the truth is, if we were trundling along and decided it was all going to be catastrophic and we have got to pull up the handbrake pretty sharpish, a lot of other EU countries would be probably be laughing at us, but I think at the same time they would probably be quite pleased we weren't going.
So I think the short answer is: legally, it doesn't look so good if you want to get out of it, but politically, it probably can be done with the support of other European leaders.
Eric Degerland asks when UK passports are going to change.
Kevin Connolly says:
This takes us to the heart of an issue that lots of people really care about. It will be a real and palpable sign of Brexit when there is a new UK passport without the words "European Union" on the front cover.
Sadly, the short answer is we don't really know when the change will come about.
But we can say that the cheapest thing for the government to do would be to phase in the new passports as people's old ones expire.
So if you're looking forward to getting back that blue hard-back passport we had in the old days, you may have a long time to wait.
The BBC's Reality Check team answered some of your questions about Theresa May's plans for EU citizens living in the UK.
Will Irish citizens be exempt from this five-year residency requirement, and continue to be afforded equal treatment with UK nationals?
Yes, Irish citizens residing in the UK will not need to apply for settled status to protect their entitlements as the UK government is committed to protecting the Common Travel Area arrangements.
Would EU citizens still be able to move to the UK in the next two years until March 2019?
Yes, they would. The UK is a member of the EU until it withdraws, so the freedom of movement rules will apply until then.
Why shouldn't British courts have full jurisdiction over the rights of EU citizens living in the UK? Wasn't that the whole point of Brexit?
The UK government says the European Court of Justice will not have jurisdiction over EU citizens' rights. The EU demands that it does. This is an important sticking point in the Brexit negotiations.
How can a lifetime stay be guaranteed? Could a future government change the law?
Once the UK leaves the EU, any future government will in principle be able to propose amendments to the rules and the UK Parliament would decide on the new law.
I plan to retire to France within the next two years and buy a property. Will this be possible after Brexit?
You can buy property and retire anywhere in the world, subject to the rules of the country you are retiring in. So, you'll be able to do that but we don't know what your exact rights will be until the UK and EU conclude the citizens' rights negotiations.
I'm an EU national living in the UK but my wife is from outside the EU. Is her status going to change?
Your wife, as a family member of an eligible EU citizen who has been resident in the UK before we leave the EU, will also be eligible to apply for settled status with you, provided that she too meets the settlement criteria and has been in a genuine relationship with you while resident in the UK.