This article is updated regularly in response to new developments.
At 11 p.m. GMT on March 29, 2019, the United Kingdom will officially leave the European Union — an economic and political partnership of 28 countries — bringing to an end 46 years of British membership.
Brexit is set to be the most important constitutional shake-up the UK has known since it joined the then six-nation European Economic Community in 1973, and represents the first time the European institution has lost a member.
The exit date marks the end of the two-year negotiating period formally set in motion when the UK triggered Article 50 of the EU Treaty in March 2017. British people voted to leave the EU by 52% to 48% in a June 2016 referendum.
An exit deal struck between London and Brussels and agreed by EU governments has encountered strong hostility in the British parliament, whose approval is needed for it to take effect. The crucial vote is due to take place on January 15 – and if the agreement is rejected, as many expect, the outcome is highly uncertain.
As the clock ticks by towards March, focus on a potential UK departure with no ratified agreement has increased. On January 15, MPs rejected an agreement, a year and a half in the making, between the government and the EU.
What had the UK and the EU agreed?
In November the British government and EU leaders approved a deal on the terms of the separation — the Withdrawal Agreement — and a political declaration on the nature of future EU-UK ties.
The near 600-page Withdrawal Agreement would be legally binding and settles the key “divorce” issues: the UK’s financial obligations to the EU, citizens’ rights, and arrangements for the Irish border — which will become the only land frontier between the UK and the EU. Both sides agree this must remain open, but the historically sensitive and complex issue has bedevilled the talks.
The exit deal also would have paved the way for a planned transition period to come into effect after the UK’s departure. This would run until the end of December 2020, although it could be extended.
During this period many existing arrangements would remain in place, allowing for more time to sort out future EU-UK relations and avoid an abrupt “cliff-edge” exit.
The Withdrawal Agreement was accompanied by a much shorter Political Declaration on future relations. This was not legally binding — but should have formed the basis for a trade agreement to be negotiated after Brexit.
Although the UK parliament has rejected the deal, the EU has said it is still willing to honour it, if MPs change their mind. On the other hand, the European Commission and European Council have insisted that any changes to the deal will require concessions first from the UK side.
The ongoing UK row over Europe
British Prime Minister Theresa May has always insisted the deal is in the national interest and there is no viable alternative. She arguee that it delivers on the referendum result: an end to free movement, an end to huge UK payments to the EU, an exit from the unpopular EU structures on farming and fishing.
At the heart of the debate in the United Kingdom is the balance to be struck between two objectives: a desire for independence, sovereignty and autonomy against the need to retain access to European markets, which, the EU has always insisted, means adhering to EU rules.
Echoing the ruling Conservative Party’s decades-long internal conflict over Europe, the deal has brought hostility from both supporters and opponents of Brexit. A “backstop” mechanism to guarantee an open border on the island of Ireland, contained in the agreement, proved to be a major stumbling block.
Why is the Irish border issue so complex?
May's main challenge has been opposition in her own party, given that other political groups all oppose her proposal.
Eurosceptics amid ruling Conservative ranks strongly opposed May’s Brexit plan, with many calling for the UK to leave the EU with no deal. They argue the deal tied the UK too closely to EU rules, compromising independence perhaps far into the future.
Equally, several pro-EU MPs have also vowed to vote against a deal which, in their view, would leave the UK worse off than it had been inside the bloc. Some have joined calls from opposition parties for a second referendum to see whether the country has changed its mind on Brexit.
May will now have to present a new proposal with the aim of winning over some opponents. There is a majority in parliament opposed to leaving without a deal, but little consensus on what the deal should look like.
After Brexit day
A successfully ratified deal would pave the way for an orderly UK exit from the European Union, quickly followed by full trade talks between the two sides – which were not allowed while Britain remained a member.
Under the withdrawal terms — and subject to an agreement being ratified — this is also when a 21-month transition period would begin, keeping many existing arrangements in place while allowing for more time to sort out future EU-UK relations.
If no UK-EU trade deal had been agreed by the end of December 2020 — although an extension to this period is possible under the draft accord — the famous backstop would come into force to keep the Irish border open. This would set up a basic UK-wide customs union with the EU, but with Northern Ireland more deeply integrated with the bloc's rules.
What happens in a 'no-deal scenario'?
Failure to secure formal approval from the UK and EU Parliaments would likely put the focus even more sharply on “no deal” preparations, which have already been set in motion.
Many political leaders, institutions, companies and individuals have warned of severe disruption and economic damage — with the UK being hit worse than the EU. On November 28 two major reports by the UK Treasury and the Bank of England assessed the potential damage to the economy of various Brexit scenarios.
However, Brexiteers have long dismissed “Project Fear” forecasts and some argue that the UK could survive perfectly well under World Trade Organization (WTO) rules.
The UK government has published a series of papers advising citizens and businesses on the consequences and how to prepare for no deal.
The European Commission’s publication on its Brexit plans — including for no deal — warned of “significant delays” at borders and said there would be “no specific arrangement” for EU citizens living in the UK or Britons in Europe.
How did it all come to this?
Check out our history of the United Kingdom's complicated relations with the European Union in four parts: