And to potentially further delay matters, after Wednesday, the U.K. will remain part of the EU for at least two years, the time Article 50 allows for negotiations over Britain’s exit. According to the text of the statute, however, that interval can be extended if the European Council and the U.K. agree to do so.
But others warn that March 29 could invite a reprisal of “Black Wednesday,” the infamous 1992 collapse that occurred on the day Britain withdrew from the European Exchange Rate Mechanism, causing the pound to collapse by 15 percent. Earlier this year, uncertainty over the U.K.’s departure from the EU caused the pound to tumble after May outlined her commitment to a “hard Brexit” that would extract the country from the European single market. When May reiterates that promise on Wednesday, some fear the pound could suffer another hit. But her decision to announce Brexit day a week in advance has allowed the markets to take it into account, likely avoiding any immediate damage to the pound, according to Richard Whitman, senior research fellow at Chatham House.
So despite the unprecedented nature of Wednesday’s events, British society—the government, financial markets, and average citizens, at least—seem to be approaching the portentous day in a decidedly British way: calmly. Yet even as Brits plan to carry on as usual, there is hardly anything normal about what is about to happen.
Brexit negotiations will come in two phases: the first, which begins on Wednesday, is a battle over what the divorce settlement between the U.K. and EU will look like. The two most important issues in those proceedings concern how much the U.K. will have to pay the EU upon leaving—current estimates are around $60 billion, though Brexit Secretary David Davis swore on Monday the sum would be “nothing like that.” The other issue is securing the rights of EU citizens living in the U.K., and U.K. citizens living in Europe. May has said she would like to reach an early agreement to secure the reciprocal rights of EU and U.K. citizens; arriving at such an agreement in the first few months of negotiations could be an easy win for both sides. In the meantime, the rights of EU citizens in the U.K. will indeed be used as “bargaining chips” in Brexit negotiations. Many families have already begun preparing to leave the country, fearing their loved ones may be denied the right to live or work in a post-Brexit Britain.
“There will be a degree of … treading water for the next six months,” Leonard said. “The big crunch point will be in December  when there will be an agreement about the divorce.” Once leaders on both sides reach an amicable divorce settlement, they will begin tracing the contours of their future relationship—in particular, the future of trade between them.
On Monday, the Labor Party and UKIP both issued six “tests” for Brexit, providing a general notion of how both opposition parties will evaluate the eventual exit deal. On Thursday, the U.K. will publish a white paper detailing its intention to introduce the Great Repeal Bill, a measure that would transfer all EU laws into U.K. law while repealing the European Communities Act 1972, which marked the U.K.’s accession to the EU 45 years ago. Parliament would then have to vote to remove or modify EU laws that currently apply to the U.K., potentially returning some powers to the devolved parliaments and assemblies of Scotland, Northern Ireland, and Wales. Then, on Friday, the EU will respond to May’s letter with draft negotiation guidelines for the remaining 27 member states, outlining the bloc’s priorities for the ensuing two years of negotiations. A month later on April 29, representatives from all 27 states will meet for a special Brexit summit to discuss their negotiating position.