Hard exit.

Much of the discussions so far have centered on whether it’ll be a “soft” Brexit or a “hard” Brexit. A “soft” Brexit would allow the U.K.’s relationship with the EU to remain mostly unchanged: in other words, with the U.K. having access to the single market, and with the free movement of EU citizens. A “hard” Brexit, on the other hand, would see the U.K. negotiators refusing to compromise on the unrestricted movement of EU citizens, thereby losing access to the single market. In reality, since immigration is one of the reasons Brexit occurred, a final settlement is likely to fall somewhere in between a “soft” and “hard” Brexit.
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While England and Wales voted to leave the EU, Scotland and Northern Ireland voted overwhelmingly to remain. Brexit affects them, too. The Scottish government says it wants to secede from the U.K., calling for talks with the U.K. government on an independence referendum sometime between the fall of 2018 and the spring of 2019. The U.K. government says it won’t negotiate. May had previously said “now is not the time” for a Scottish referendum on independence. Scotland’s desired timetable for an independence referendum would fall within the two-year period of negotiations between the U.K. and the EU. A Scottish independence campaign run in parallel with the Brexit talks would considerably weaken the U.K. government’s hand. 

The Atlantic: Brexit: So What Now?, 29 March 2017