On 23rd of June, 2016, the UK voted in a referendum to leave the EU. This leads to the following questions:
Also, see the related post on Travel.SE.
The UK will most likely remain a member of the EU until at least 2018, potentially leaving the bloc 29 March 2019 11pm UK time.
All of the current EU/EEA laws still apply until that date. No one really knows what will happen afterwards.
The government has set up a newsletter for EU citizens living in the UK, which you can join to get updates, including when and if the new so called "settled" status will go live, which will hopefully replace the current Permanent Residence status which will lose its validity.
Although the referendum is passed, and Article 50 has been invoked, there are still not many hard facts regarding what will change. Based on our current (as of 29 March 2018) understanding, the UK government and the EU delegates will try to get an agreement until around October 2018 leaving enough time for it to be voted on and ratified by all parties by the two-year cut-off date of March 2019.
Note that while Article 50 was invoked on the 29 March 2017, it only means that the formal withdrawal process has been started, and the two parties (UK and the rest of the EU) will have two years to get an arrangement on the future, but even that two-year period is subject to modification by unanimous agreement of the parties. Until that arrangement is made (or the two year period is passed without any resolution), the UK will still remain a full member of the EU, and all EU treaties will still fully apply.
Although it is possible that there will be an arrangement within a few months of invoking Article 50, because there are a lot of treaties to renegotiate, it is more likely it will actually take the full two years for everything to settle, until which date the UK is still part of the EU, and all of the EU treaties still apply. It is also possible that because of the amount of treaties involved the two parties might extend the two year deadline.
What will happen after the arrangement has been made: no one knows. Whether EU citizens living in the UK, and UK citizens living in EU will need new visas, or can still remain in the country will depend on the new rules that will be made during this period. The best thing to do is to constantly check upon the news on the new laws and regulations that will be in place once the UK leaves the EU in both the UK and in the rest of the EU.
As of 1 April 2018 the following four options are the most likely scenarios to happen (in decreasing order of likeliness):
The UK and the EU agree to a non-EEA (usually called Canada-plus-plus) style deal:
The UK and the EU do not agree to any kind of deal:
For EU citizens living in the UK: This would mean EU citizens living in the UK will possibly get into a legal limbo after the Brexit day. However it is likely that the EU Withdrawal Bill will come into force, which will put all EU regulations (including ones for immigration control) into UK law, meaning their rights will be preserved for a while. Afterwards it is still likely the UK government will replace these provisions with a Settlement status as described above.
For UK citizens living in the EU: similarly they will get into a legal limbo after Brexit day, with their status dependent on the country they are living in. However it is still likely that in this scenario they will get a similar deal as described above meaning they will be able to remain in the country they are living, but won't be able to freely move to another EU country.
The UK and the EU agree to a Norway style (usually called Norway-minus) deal, and will remain in the EEA but not the EU:
For EU citizens living in the UK: Most likely in this case the UK will remain in the EEA, all current laws will remain in force, and free movement will continue, however there might be slight restrictions on newcomers.
For UK citizens living in the UK: Similarly EEA laws will still apply, and UK citizens in the EU will be able to move freely, but there might be slight restrictions on newcomers.
The UK remains in the EU: Nothing will change
Until we know more of the new laws and regulations at the moment there is one and only one for sure way for an EU citizen to remain in the UK after Brexit - naturalisation as a British citizen. For that the EU citizen needs to have been living in the UK lawfully(*) for 6 years (5 years to obtain Permanent Residence, and one more year in the PR status to be eligible for naturalisation). Or 5 years if married to a British citizen (5 years to obtain Permanent Residence, and then you can apply for naturalisation immediately)
(*): note that this includes you have Comprehensive Health Insurance cover for the full 5 year period until you get the PR status. If you are working full-time for the entire period this is most likely okay, but if you've been unemployed, or a student you might have issues obtaining PR. You also have to prove at least 5 years worth of residence and 5 years worth of having an income (or Comprehensive Health Insurance), so even in the best case scenario at least 10 documents (for example 5 years worth of council tax statement, and 5 P60s).
Based on current details although the PR status will lose its validity on Brexit day, there are plans to introduce a new status, called "settled", which will have very similar rights to the current PR status. However this status is not yet formalised and not yet voted on, so how it will exactly work is currently unknown.
There might be also one other possible route if you have been living in the UK long enough: if you have been legally living in the country for 10 year then in case of a Brexit, even without any other legal status on hand (for example if every PR is invalidated), you should still be able to settle and obtain an ILR applying via the long residence route.
Deloitte's a guide to Brexit gives a good overview, which echoes SztupY's answer:
As the negotiations progress, we still unfortunately lack clarity from the UK government. However, as people cannot simply wait and see we are forced to speculate based on available information and statements by those involved.
One important thing to remember is that freedom of movement is not derived from the EU, it's actually part of the European Economic Area (EEA) rules. So while the UK voted to leave the EU, it did not vote on membership of the EEA and due to issues like the Irish border and Gibraltar it may be difficult to leave it, so full freedom of movement may continue.
Are UK citizens working in the EU affected?
The EU seems committed to looking after EU citizens, including British ones even after Brexit. The EU has designated individual rights as a high priority and even if the UK walked away with no deal, it seems likely from statements by key people such as Guy Verhofstadt that UK citizen's already in the EU exercising their EEA treaty rights would be protected. Individual nations, such as Spain, have also said they will not require anyone to leave, without setting out detailed proposals.
In the worst case such people would be forced to return to the UK, if they could not secure residency rights in an EU country. In that case there are other issues that have not even been considered, since both sides want to avoid this situation, such as if their families would be allowed to go with them (assuming they wanted to live in the UK).
Another very bad but entirely possible outcome would be for UK citizens to become "land-locked", that is able to remain in the EU country they are in but unable to move to another one as EU citizens can. This could be extremely problematic for them, because many EU companies do cross-border business regularly.
One other potential consequence is a flood of elderly and/or unemployed expats back to the UK post Brexit, putting a great strain on local authorities and the NHS. For example, if they had retired to Spain but then lost their right to remain there.
The Irish and Gibraltar/Spain borders are another big unknown. Many people cross them daily for work. Some UK politicians are calling for an end to this free movement, which would presumably make them unemployed at the very least. For Gibraltar the very worse case would be having to rely on food aid deliveries from the UK by air.
Are EU citizens working in the UK affected?
The UK government has said that they can stay, but it isn't clear what rights they will retain yet. For example, if they need to visit family for an extended period in another country, will their residency rights in the UK lapse?
Should the UK walk away from negotiations with the EU, the government has said it would not deport EU citizens already here, but there is no legal mechanism to prevent them reneging.
Are non-EU citizens working in the UK affected?
The UK government has mentioned introducing a "points based system" for immigration post-Brexit. It has also promised to reduce net immigration to the "tens of thousands", which would severely impact non-EU citizens trying to reunite their families or people trying to hire foreign staff.
To give you an idea, there are already tens of thousands of EU family reunion immigrants every year, so if the government stuck to its promise to EU citizens there would be have to be a complete end to all other forms of immigration. Similarly, UK universities are reliant on non-EU students for income, and their numbers would exceed this promise too.
Given this is seems likely that, while not as a direct result of Brexit since the UK already has full control of immigration for non-EU citizens, things will get a lot worse for non-EU citizens. The ones already here may find it much more difficult to bring family members, or to visit family members, or to obtain permanent residency rights in the UK.
What other consequences might 'Brexit' have on EU/UK citizens?
This is a rather broad question, but in relation to residency rights the other group who will be negatively affected are families. Currently if a British citizen works in, say, France, they can have their family join them from anywhere in the world. If they eventually return to the UK, their family can go with them, regardless of UK immigration rules. That right may be lost, making working in EU countries much less attractive since even if they have less draconian immigration systems the UK citizen might be forced to abandon their family if they themselves must return to the UK.
Another short answer is "it will not affect us at all".
After all, the referendum was about leaving the EU. The EEA is a separate treaty, and the UK is not leaving it, as far as we know.
