Virginia, US
As we draw closer to 23 June, I thought it would be helpful to take a step back from our discussion on the potential impact of Brexit and EU reform from our and look at how the Brexit referendum will work.  
The question for the UK is,  “Should the United Kingdom remain a member of the European Union or leave the European Union?”,  and the  result of the vote will be announced on Friday 24 June.
What exactly is a referendum, I hear you say?
A referendum is a general vote by the electorate on a single political question, which has been referred to them for a direct yes or no decision. Technically speaking a decision made by referendum is not legally binding. The principle of Parliamentary Sovereignty means that Parliament is free to pass any laws it chooses, and is not bound by a public vote or an order of the government. In practice however it is extremely unlikely that a Parliament comprised of elected MPs would thwart a decision approved by referendum.
Who can  vote?
Eligibility will be based on the criteria for voting in a general election, which means citizens of most EU countries will not be allowed to take part. Anyone over the age of 18 who falls into one of the following groups can cast a vote:
  • British citizens resident in the UK
  • British citizens resident overseas for less than 15 years
  • Citizens of Ireland, Malta and Cyprus resident in the UK
  • Commonwealth citizens resident in the UK
  • Commonwealth citizens resident in Gibraltar
  • Members of the House of Lords
If we wake up on 24 June to a no vote result, will the UK be out of the EU with immediate effect?
No. If the UK was to vote to leave the EU then British MPs would be required to pass a law enacting the nation’s decision. This will include a repeal of the 1972 European Communities Act and ratification of the withdrawal agreement.  Article 50 of the EU treaty allows  a member state to  withdraw and gives a deadline to negotiate terms within two years, with some scope to extend this period  if trade and immigration issues have not been successfully concluded in that time. At the end of this 2 years or extended period,  Britain’s membership will simply expire. There are a great many theories as to the political, economic and social consequences of a vote to leave the EU. The greatest uncertainty associated with leaving the EU is that no country has ever done it before, so no one can predict the exact result. Leaving the EU would involve complex and lengthy negotiations, with talks held on the future of the UK's relationship with the EU, including whether it could still have access to the single market and these negotiations would be expected to continue into 2018 in the event of a no vote.
And in the event of a yes vote?
In the event of a vote to stay in the EU, things will continue as they are and ‘purdah’ will be lifted once the vote is complete. Purdah is a longstanding convention whereby governments refrain from making any major announcements in the run-up to general elections or referenda to avoid influencing their outcome. As such, we may see changes in the immigration rules later in the year, which would otherwise normally take effect on 6 April (in line with the tax year).