Now that Britain has voted to leave the European Union, actually getting out won't be easy – and the fallout goes beyond Britain.
What's the first step?
Under Article 50 of the Treaty on European Union, Britain is supposed to give notice of withdrawal to the European Council, which is made up of the heads of each member state. During the next two years, both sides would negotiate a new arrangement. That deadline can only be extended by unanimous consent, and any new deal would have to be approved by a majority in the European Parliament and every EU state. During this period, Britain would remain a full member of the EU.
What else could happen?
Britain could avoid that process altogether and simply pull out on its own by revoking British legislation that brought it into the EU's predecessor in 1973, the European Economic Community. But that would make negotiating a new trade deal with the EU tricky, and all EU legislation, along with free trade, would end immediately.
When would this happen?
Prime Minister David Cameron has said that if there is a leave vote he would trigger Article 50 "immediately." He could hold off and use a leave vote as a way of negotiating a new deal before triggering Article 50, but that would depend on the EU's willingness. And any new deal would still require the approval of the EU and the 27 remaining member states.
What about the political fallout?
Mr. Cameron said on Friday he would resign as Prime Minister, promising to have a new leader in place by October. Under a leave scenario, Conservative MP Boris Johnson and Justice Minister Michael Gove are seen as possible replacements, as both were prominent Vote Leave campaigners. The future of other pro-Remain cabinet ministers, including Chancellor of the Exchequer George Osborne, could also be in doubt. Mr. Osborne was also seen as a future prime minister.
Who else would be affected?
Life for Bank of England Governor Mark Carney could get difficult. Mr. Carney raised the ire of the Vote Leave campaign by issuing several dire warnings about the economic consequences of exiting the EU. He has insisted it was his duty to point out risks to the economy, but many on the Leave side felt he went too far. Mr. Osborne appointed Mr. Carney, so if the Chancellor goes, Mr. Carney would lose a big backer.
What about the rest of the EU?
Britain leaving would throw the EU into crisis and could fuel growing anti-EU sentiment in other countries. There is sizeable support for leaving the EU in countries such as Italy, Greece and even Germany. And the EU's relationship with Britain could become toxic, given that Jean-Claude Juncker, the President of the European Commission, has suggested that "splitters will not be welcomed back with open arms."
Scottish First Minister Nicola Sturgeon, who leads the Scottish National Party, has hinted that she may push for another referendum on Scottish independence if there is a leave vote. In 2014, 55 per cent of Scottish voters chose to stay in the U.K.
What about London's financial centre?
London has become a world financial capital mainly because of its free access to other EU countries under so-called "passport rules." More than 100 banks have set up in the city as a gateway to Europe. That could end if Britain leaves. And London has already faced pressure inside the EU to give up trading in euro-denominated derivatives, a trillion-dollar market. The European Central Bank wants to move that trading to a country that actually uses the euro, like France or Germany. So far Britain has been able to fend off the challenge by invoking EU rules. But if the country leaves, there will be no stopping the ECB.