This article is updated regularly as events unfold.
The United Kingdom left the European Union — now an economic and political partnership of 27 countries — on January 31, 2020, bringing to an end 47 years of British membership of the EU and the institutions that preceded it.
Attention has since turned to negotiating the future EU-UK relationship beyond a stand-still transition period that ends on December 31, 2020 — heralding abrupt and major changes unless there is an agreement.
Meeting this tight deadline was a huge challenge, even before the onslaught of the coronavirus pandemic which has overwhelmed both sides. But the British government has rejected calls to extend the transition.
"Brexit" — the term used to describe Britain's EU departure — represents the most important constitutional shake-up the UK has known since it joined the six-nation European Economic Community in 1973. It is also the first time the European institution has lost a member.
The UK voted to leave the EU by 52% to 48% in June 2016. It followed decades of increasing hostility to the European project in the United Kingdom, reinforced in recent years by a rise in nationalist sentiment, particularly in England. Other factors such as austerity and frustration with traditional politics have also been cited as reasons — amid a wider debate over the role of the nation state and the rise of populism in an age of globalisation.
The aftermath has increased strains between the UK's individual countries: England (53%) and Wales (52.5%) voted to leave the EU, whereas Scotland and Northern Ireland voted by 62% and 56% respectively to remain. Other divisions have also been exposed: between metropolitan areas and small towns for example, and different age groups and social classes.
There has been concern that the prolonged, acrimonious process has shifted attention from major global challenges, not least the battle to address the climate emergency. For many in Europe, the prospect of an institutionalised rift between the UK and the EU weakens the continent at a time when the likes of America, China and Russia are becoming increasingly assertive.
Latest developments and stories (to May 15):
Coronavirus casts vast shadow over post-Brexit talks
No sooner had negotiations begun on the UK's post-Brexit relationship with the EU, than the coronavirus pandemic effectively put a halt to proceedings.
A first round of talks took place in early March, but subsequent face-to-face talks were suspended for six weeks.
At the end of a second round of talks which took place by video links in April, the EU's chief negotiator again expressed frustration at the lack of progress, effectively accusing the UK of dragging its feet.
Michel Barnier used similar language at the end of a third round of discussions in mid-May, accusing the UK in a statement of a lack of ambition. His British counterpart David Frost agreed that little progress had been made, accusing the EU in his statement of adopting an ideological approach.
A further round of talks is scheduled for the week beginning June 1.
Video connections are not seen by critics as a satisfactory substitute for face-to-face meetings, given the detail involved and the dozens of negotiators on each side.
Some key figures, including Barnier, the UK's chief negotiator David Frost, and most notably the UK Prime Minister Boris Johnson, have been struck at various stages by COVID-19.
Recent months have seen energies on both sides distracted by the pandemic, but very soon decisions will need to be taken on post-Brexit ties.
Two deadlines: December — and June
The negotiations cover a new trade deal and the terms of the future relationship — taking in a wide range of areas including good and services, fishing and farming, security cooperation, data policy, education and science.
The deadline is the end of the year and the expiry of a post Brexit “transition period” that began when the UK formally left the EU on January 31, keeping most arrangements temporarily in place.
The divorce agreement allows for a two-year extension of the transition period to give more time for negotiation. Despite the coronavirus pandemic Britain has ruled that out having legislated to that effect — although the full effect of the global health and economic crisis in the coming months remains to be seen.
Under the binding terms of the divorce agreement, a decision must be made on any prolongation by the end of June. Some voices have called on the UK to seek an extension: they include the head of the International Monetary Fund (IMF) Kristalina Georgieva, the European Parliament's largest group the European People's Party, and the anti-Brexit campaign group Best for Britain.
Critics say the shorter deadline provides nowhere near enough time to conclude a deal embracing all aspects of future EU-UK relations. One possibility evoked is for a simpler, more “bare-bones” trade deal to be struck, leaving the detail of other policy areas to be sorted out later.
'Serious differences' between EU and UK
Both sides outlined sharply contrasting positions as they flexed their muscles in advance of the talks. Officials in Brussels were reportedly taken aback by the stance of Boris Johnson’s government — which is seeking a far more distant, independent relationship with the EU than the one sought under the previous UK prime minister, Theresa May.
EU leaders have called for an “ambitious” wide-ranging agreement — subject to conditions. Setting out the EU's position, chief negotiator Michel Barnier said there could be no trade deal unless Britain agreed to a "level playing field" — a commitment included in the EU-UK divorce deal (see below) — and did not undercut EU regulations. He has since said that "serious differences" remain between both sides.
But during the pre-talks period Johnson, other ministers and officials, all highlighted the UK's stance: that being able to diverge from EU rules and standards was the essence of Brexit and the UK’s “new footing as an independent sovereign nation”.
Britain is seeking a narrower free trade deal similar to those the EU has done with countries such as Canada. Brussels stresses it has always been clear that the UK’s geographical proximity to the EU, and degree of economic integration with Europe, mean the same rules cannot apply.
'Little progress' made in talks
At the end of the third round of talks in mid-May, Barnier said the UK had failed to engage on the "level playing field" commitment on competition, while his counterpart Frost effectively accused Brussels of moving the goalposts.
Barnier was equally disparaging over the UK's stance on matters such as governance, law enforcement, and sustainable development -- adding that the British seemed to misunderstand the consequences of leaving the EU's Single Market and Customs Union.
On the British side, Frost accused Brussels of unfairly trying to tie the UK into EU rules and standards, and said EU demands on fishing were incompatible with UK sovereignty.
Without an accord, the UK will thereafter be legally considered a "third" country by the EU, creating significant barriers to trade and other aspects of life. Both sides’ red lines have raised fears that no deal may be reached, bringing an abrupt, damaging “cliff-edge” at the end of 2020.
The UK's departure brings another headache for the EU, in the shape of a hole in its budget for the next few years. A summit in February aimed at agreeing the bloc's long-term financing plan ended in failure.
Brexit day: UK finally leaves EU on January 31
The process plunged the UK into its worst political and constitutional crisis since the Second World War. The country's EU exit was repeatedly delayed amid a period of deadlock and turmoil in the British parliament — which ended after Boris Johnson replaced Theresa May as prime minister, renegotiated the divorce deal, and led the ruling Conservative Party to an emphatic election victory in December 2019.
The UK left the EU on Friday, January 31 at midnight CET (11pm UK time). Any remaining uncertainty was removed after the divorce deal was ratified by both the British and European parliaments — legal requirements for its terms to take effect.
The European Parliament passed the deal on January 29 by a large majority, despite expressing concerns over the rights of Britons living in the EU, and especially the rights of EU citizens resident in the UK.
In the UK, the Conservatives' election victory ensured that the legislation to implement Brexit was duly passed by parliament, receiving royal assent on January 23.
EU leaders welcomed the "clarity" brought about by the election result. However, there has been scepticism over whether the post-Brexit transition period in 2020 allows enough time to strike a trade deal and work out the future relationship.
Brexit could also increase tension further within the UK's four nations. Scotland — which has seen renewed calls for independence — and Northern Ireland both saw significant anti-Brexit votes at the election.
Brexit divorce deal takes effect
The UK ceased to be a member of the EU from February 1, and is no longer part of the bloc's institutions. Its departure took effect under the terms of the revised divorce agreement struck by London and Brussels in October 2019.
The deal consists of a Withdrawal Agreement on the terms of departure, accompanied by a Political Declaration on future ties.
The divorce terms in the Withdrawal Agreement cover matters such as the UK's financial settlement, provisions for Northern Ireland, and safeguards for the rights of EU citizens living in the UK, and Britons living on the continent.
Under the divorce deal, a transition period came into effect upon the UK’s departure and will run until December 31, 2020. During this period many existing arrangements will remain in place.
The existing rules still in force during this period cover matters including freedom of movement (the right of EU citizens to move to other EU countries to live and work), cross-border travel and personal rights.
The UK intends to introduce a new immigration policy taking effect in January 2021. EU nationals will no longer have preferential treatment, under government plans which include a points-based system to attract skilled workers.
What happens under the ratified UK-EU Brexit divorce deal?
The revised Withdrawal Agreement keeps the provisions in the previously negotiated deal on the key “divorce” issues: settling the UK's financial obligations to the EU, and setting out arrangements for Northern Ireland, and citizens' rights.
These safeguard residency and social security rights for EU nationals living in the UK and Britons in the EU, and maintain freedom of movement until the end of the transition period.
The arrangements came into force when the UK left the EU at the end of January under the terms of the ratified deal, and have the force of an international treaty.
The main change from the deal negotiated by Theresa May's government is that the controversial Irish "backstop" contained in the previous accord (see below) — to keep an open border on the island of Ireland — is scrapped in the new agreement.
Arrangements for Northern Ireland
Brexit means that the border between Northern Ireland (part of the UK) and the Republic of Ireland (part of the EU) – one of the most politically sensitive frontiers in the world — now becomes the European Union's only land border with the United Kingdom. All sides agree this must remain open, but the historically sensitive and complex issue bedevilled the divorce talks.
Under the revised deal, Northern Ireland will leave the EU's customs union with the rest of the UK, which wants to pursue an independent trade policy. But in practice, after the end of the transition period it will follow EU customs rules and be subject to EU oversight.
The North will remain aligned with some aspects of the EU's single market — and apply EU law on VAT (Value Added Tax) rules.
Customs and regulatory checks will not be carried out on the island of Ireland, but at ports — effectively creating a new regulatory divide in the Irish Sea between Great Britain and Northern Ireland.
This arrangement is effectively an insurance policy to avoid a hard border — such as border posts — and protect the cross-frontier economy between Northern Ireland (part of the UK) and the Republic of Ireland (part of the EU), post-Brexit.
It replaces the plan in the previous, rejected withdrawal deal known as the backstop. In the absence of a trade deal or an alternative solution, the idea was for the whole of the UK to remain in a customs union with the EU, while Northern Ireland would be aligned even more closely with EU rules. The backstop's removal means this arrangement will no longer happen.
The revised agreement has similarities with an original EU proposal for a Northern Ireland-only backstop — which was rejected by Theresa May's government — but is more complex, and has one key difference in that legally, Northern Ireland will be in the UK customs union.
The accord deals with the issue of Northern Irish consent for these changes: Northern Ireland's assembly will be able to decide on whether to keep the new arrangements — but only four years after the transition period.
How important is the Political Declaration on future ties?
There are also changes in a revised Political Declaration on the shape of future EU-UK relations, agreed as part of the divorce deal. the document provides a framework which could form the basis for a future trade agreement.
The UK government has signed up to various assurances on future trade competition and other matters. These include a commitment to a "level playing field" with the EU over issues including state aid, competition, social and workers' rights, the environment and climate change.
The declaration relates to a future EU-UK economic relationship where the UK opts for a Free Trade Agreement (FTA). But in return for zero tariffs and quotas, the UK makes "robust commitments" to ensure "open and fair competition".
However, the declaration is engagement is legally non-binding — as opposed to the withdrawal agreement which has the force of an international treaty. Critics are wary that the commitments may not be watertight — especially given the Johnson government's avowed intention to diverge from EU rules and forge an independent trading path.
In the original declaration negotiated by the previous UK government, Theresa May envisaged the UK remaining closely aligned to the EU.
Many observers argued when the agreement was struck, that negotiations over future ties risked being much more complicated and harder to resolve than the divorce deal. The evidence of the first rounds of talks in the spring of 2020 would appear to bear this out.
Running parallel to the Brexit saga has been the UK's evolving relationship with the United States, with which Britain hopes to strike a future trade deal. Trade experts say the UK faces a key choice over regulatory alignment: whether to stay close to EU rules to access the European market, or follow American regulation.
Why might December 2020 see another 'no-deal scenario'?
Throughout 2019, the fear for many on both sides of the English Channel was that the UK could "crash out" of the EU without an agreed deal on either the terms of the divorce or the future relationship. Had that happened, legal arrangements covering many aspects of everyday life would have abruptly ceased to apply.
But the threat of such a "no deal" exit in January 2020 vanished with the UK election result in December 2019. The UK went on to leave the EU under the ratified withdrawal agreement. Its provisions — on the financial settlement, citizens' rights, and Northern Ireland — are now protected under a binding treaty whatever the outcome of negotiations on future ties, as explained above.
The new "no deal" that is being talked about refers not to Britain's exit from the EU — but to a potential failure to reach agreement on future relations by the end of the 11-month transition period.
The formidable challenge of securing a trade deal with the EU in a few months during the transition period — a task that usually takes the bloc several years — means the UK could be staring at another economic "cliff-edge" in 2020.
Failure to secure a trade deal would hit the UK's economy but also those of its closest continental neighbours — and Ireland. It would bring an immediate change in the trading relationship between the UK and the EU.
Other important matters such as cooperation on security and terrorism, education and science risk being left up in the air if no detailed agreement is reached on future EU-UK relations.
Warnings of economic damage and disruption
Many political leaders, institutions, companies and individuals have warned of severe disruption and economic damage on both sides of the English Channel — with the UK being hit worse than the EU.
However, Brexiteers have long dismissed “Project Fear” forecasts and some argue that the UK could survive perfectly well under World Trade Organisation (WTO) rules.
Government documents, published in early September 2019 and codenamed "Operation Yellowhammer", confirmed a grim assessment of the potential impact of a no-deal Brexit on October 31. Based on the government's own preparations for a "worst case" scenario, they contained warnings of possible food, medicine and fuel shortages.
The heightened uncertainty amid a year of British political turmoil in 2019 twice forced the UK and the EU — as well as people and businesses on both sides of the English Channel — to step up no-deal preparations, as the Brexit process dragged on without formal approval for an exit deal.
Theresa May's government published a series of papers — some updated under her successor — advising UK citizens and businesses on the consequences and how to prepare for no-deal. It said the EU would treat the UK as a "third country".
British economic sectors reliant on close, smooth arrangements with Europe warned of the dangers of new costs and restrictions being imposed overnight. Among those sounding alarm bells were manufacturing industries — including the car industry, food and drink, chemicals and pharmaceuticals – as well as aviation, the health service, tourism, and financial services. There were also warnings over farming and fishing — despite strong support for Brexit from within these two sectors.
In August 2019, after the Bank of England lowered its growth forecast for the UK post-Brexit, its governor Mark Carney warned that in the event of no deal the economy would suffer an instant hit, prices would rise and the pound would fall, and even large profitable industries would become "uneconomic".
In April 2019, a leaked letter by the government's most senior civil servant warned of an economic recession, food price rises, a severe impact on Britain's security services, police forces and legal system, and a return to direct rule by the UK government in Northern Ireland. In early August a leaked government document contained similar warnings.
In November 2018, two major reports by the UK Treasury and the Bank of England assessed the potential damage to the British economy of various Brexit scenarios.
In an assessment of EU preparations for no-deal published in July 2019, the UK House of Commons Library described the Commission's programme as one of "damage limitation" to protect the EU27 countries.
Why has the UK been so torn over Europe?
The United Kingdom's place in Europe — and vice-versa — is an issue that arguably was never properly resolved after the Second World War, and has been brought to the fore by Brexit.
Many in the UK, especially in England, have always been sceptical of the political pan-European project revered by many on the continent. The antagonism towards the EU that surfaced during Margaret Thatcher's premiership in the 1980s has been followed by decades of hostile media coverage, especially in British tabloids.
At the heart of the debate in the UK 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.
The turmoil in the British domestic political scene has cut across party lines. Internal party divisions have affected both the UK government and opposition. The ruling Conservative party in particular has long been riven between Eurosceptic and Europhile factions.
A history of UK-EU tension
Check out our series on the history of the United Kingdom's complicated relations with the European Union:
- Part 1, 1973-1990: Je T'aime, Moi Non Plus
- Part 2, 1990-2004: I'd Do Anything For Love
- Part 3, 2004-2016: Should I Stay or Should I Go
- Part 4, 2016-2017: I Will Survive
- Part 5, 2017-2019: Never Can Say Goodbye
How does the European Union work?
The EU originally developed after World War Two, with the aim of promoting economic co-operation and trade between countries to stop them from going to war again. Its members' economies are now integrated around a single market allowing the free movement of goods, people, services and capital.
Nineteen of the 28 member states use a single currency, the euro. The EU has its own institutions and passes laws affecting many issues across the union.
It highlights the benefits of membership as securing peace, promoting freedom and prosperity as part of the single market, safeguarding food and environmental standards, consumer benefits, protecting human rights, and enhancing Europe's global power.
The European Council is led by its president and is made up of the national heads of state or government, as well as the president of the Commission. It sets the EU's overall political direction but has no law-making powers.
Read more: What does the European Council do?
The European Commission promotes the EU's general interest. It is made up of Commissioners, one from each member state, nominated by national governments. It proposes and enforces laws and implements EU policies and its budget.
Read more: What does the European Commission do?
The European Parliament is the only institution directly elected by its citizens, and represents them. It also has legislative, supervisory and budgetary responsibilities.
How was the Brexit deadlock in the UK broken?
The UK finally broke the long-standing Brexit stalemate following the snap general election on December 12, 2019, which brought a crushing victory and 80-seat parliamentary majority for Boris Johnson's ruling Conservative Party.
The Tories campaigned on a promise to leave the EU by the end of January, and the prime minister's campaign slogan of "Get Brexit done" evidently struck a chord with voters. The 80-seat margin provided an ample cushion to put the UK's exit into effect.
The main opposition Labour Party suffered its biggest defeat since 1935. Under leader Jeremy Corbyn — since replaced by the party's former Brexit spokesman Sir Keir Starmer — the party's policy was much criticised. Its plan if elected was to renegotiate a Brexit deal which would then have been put to the public in a second referendum.
The pro-EU Liberal Democrats won fewer than a dozen seats — despite increasing their share of the vote — as the "Remain" vote was split. The party's campaign pledge to stop Brexit altogether if elected proved unpopular with voters.
The Scottish National Party (SNP) which also campaigned to "stop Brexit", but via a second public vote, won the vast majority of seats north of the border with England. Across the Irish Sea, anti-Brexit votes also came to the fore as Northern Ireland elected more Irish nationalists to the UK parliament than pro-British unionists.
Brexit 'clarity' follows prolonged stalemate
Opposition parties granted Boris Johnson his much-sought general election after the threat of an imminent no-deal Brexit in October was overcome.
In the absence of parliamentary approval for his renegotiated deal by October 19, the prime minister was obliged by law to seek a delay of three months from the European Union.
On October 29 the European Council President Donald Tusk confirmed that the EU had formally adopted the latest extension of the UK's membership until 31 January 2020 — with the option of an earlier departure if the renegotiated divorce deal was ratified.
The delay put paid to Boris Johnson's vow, repeated many times, that the UK would leave the EU on October 31.
Brexit deal done — but UK bill derailed
The EU and the UK announced on October 17 that they had reached agreement on a revised exit deal. It came on the day of a crucial EU summit and followed a period of intensified talks. The accord was swiftly given the green light by EU national leaders.
The deal altered previously-negotiated arrangements for Northern Ireland, and envisaged a clearer break for the UK with the EU than the accord struck by Theresa May.
Boris Johnson became prime minister in late July, but it was early October before his government submitted a detailed proposal for a new divorce deal to Brussels. He then threw out its controversial plan for Northern Ireland to reach a compromise.
A bill to implement the new deal passed its first parliamentary hurdle, but was shelved by Johnson himself when MPs rejected the government's fast-track three-day timetable to get it passed. Many felt far more time was needed to scrutinise measures that will determine the UK's relations with Europe for years to come.
How did Boris Johnson reach a revised deal with the EU?
In a nutshell, Boris Johnson made major concessions over Northern Ireland.
Out went the UK's previous proposals — much vaunted by Brexit supporters — for "alternative arrangements" including technological solutions to keep an invisible border. Instead, Johnson has agreed to a different status for Northern Ireland compared to the rest of the UK — accepting a plan very close to one the EU originally proposed.
The EU also gave ground, re-opening the withdrawal agreement it had always said was sacrosanct. Dublin and Brussels agreed to replace the controversial Irish border backstop that had plagued Brexit talks for months, and opened the door to a possible time-limit on border safeguards with a new consent mechanism.
However, Johnson's change of tack came at a price: Northern Ireland's Democratic Unionist Party (DUP), until then an ally of the government, said it could not support proposals that would create a "border in the Irish Sea".
Arrangements for Northern Ireland were a key sticking point throughout negotiations ever since the UK triggered the formal Brexit process in March 2017. Behind the details over trading arrangements are fundamental questions concerning identity. The possibility of new borders — between Northern Ireland and either the Irish Republic, or Great Britain, or both — is hugely problematic in a region with a troubled past.
'Get Brexit done': PM Johnson launches new drive for EU exit door
The UK's stance towards Brexit took on a distinctly harder edge when Boris Johnson entered Number 10 Downing Street in late July, 2019. The former foreign secretary and London mayor took over the reins after winning the Conservative Party leadership contest.
He signalled immediately a reinvigorated drive to take the UK out of the EU on October 31 — "no ifs or buts" — raising the likelihood that the country would leave the EU without a withdrawal deal.
The summer and autumn of 2019 saw the UK government significantly ramp up its no-deal preparations — since stood down — with more funds promised. The Conservative conference in Manchester had a new slogan, “Get Brexit done” — which has echoes of the “take back control” rallying cry of the “Leave” campaign during the 2016 referendum campaign.
There was further turmoil in the British parliament, where there was stiff opposition to a "no-deal Brexit". The government lost numerous votes in the House of Commons, and lost its thin majority. Several Tory rebels were expelled for opposing Brexit strategy.
Johnson suffered a humiliating defeat when the country’s highest court ruled that his government had acted unlawfully by suspending parliament.
In the end Boris Johnson was forced to compromise over Northern Ireland to win a revised deal. UK law obliged the prime minister to seek a Brexit delay from the EU, which was duly granted.
Theresa May's Brexit delay brings European election electroshock
Johnson's arrival in No 10 Downing Street followed a prolonged period of turmoil in British politics. This came to a head when Theresa May — who failed to get her EU divorce deal through parliament — became the latest in a long line of Conservative prime ministers to be brought down by Europe.
In the wake of the repeated parliamentary defeats for the EU divorce deal, the House of Commons twice forced the British government to seek to delay Brexit. In April 2019 EU national leaders met for a special European Council summit and agreed to a six-month "flexible extension" to the UK's departure from the bloc, with a new exit date set for October 31 — or earlier if its parliament approved the original withdrawal deal.
But relief at avoiding a disruptive no-deal exit was tempered by renewed uncertainty and frustration for businesses and people — especially for EU and UK expats.
The extension of the UK's EU membership also forced the country to take part in the European Parliament elections in May — and send 73 newly-elected MEPs to Strasbourg in July.
Nigel Farage's new Brexit Party, which advocates leaving the EU without a formal agreement, came top of the European vote. But there was a strong showing from pro-EU parties, in particular, the Liberal Democrats, who wanted to reverse Brexit altogether.
Britain's two main parties — the Conservatives and the Labour opposition — were severely punished by voters. Many Conservatives are furious at the failure to “deliver Brexit”, while Labour was accused of sitting on the fence.
The results indicated that opinion in the UK had become still more polarised over Brexit.
Why did the UK parliament repeatedly reject Theresa May's deal?
Theresa May's withdrawal deal was negotiated by London and Brussels over an 18-month period and approved by the 27 other EU governments in November 2018. It was rejected three times by the UK parliament between January and March 2019 — leading to May's resignation and her replacement by Boris Johnson.
The former prime minister insisted her negotiated withdrawal agreement was in the national interest and there was no viable alternative. She argued that it delivered on the referendum result: an end to free movement, an end to huge UK payments to the EU, and an exit from the unpopular EU structures on farming and fishing.
However, the agreement brought hostility from both supporters and opponents of Brexit. In parliament, an alliance of forces resulted in the successive defeats for the government.
The main Labour opposition said the deal did not meet its six Brexit tests.
Derailed by the backstop
To guarantee an open border, the backstop envisaged the UK remaining in a "single customs territory" with the EU, in the absence of a free trade deal or an alternative solution. It proved to be a major stumbling block in the negotiations.
Eurosceptic critics, including the Conservative anti-EU European Research Group (ERG), suspected it would have kept the UK strapped permanently to EU trade policy. EU sources pointed out that the UK-wide mechanism in the withdrawal agreement was included at the UK’s request, to avoid splitting off Northern Ireland from the rest of the UK.
Northern Ireland's Democratic Unionist Party (DUP), on whose support the May government depended, has always vehemently opposed any move it believes might separate Northern Ireland from the rest of the United Kingdom. Under the backstop, as set out in May's deal, Northern Ireland would stay aligned to some EU rules.
Revisions fail to stop defeats
As the clock ticked down towards the original March 29 deadline, the UK and the EU said they had agreed a revised Brexit deal following weeks of deadlocked talks between London and Brussels.
EU27 leaders had refused to alter the text of the withdrawal agreement. But Theresa May said she had secured legally-binding changes over the backstop’s application. The British parliament had voted to seek “alternative arrangements”.
The parliamentary deadlock prompted moves by MPs from different parties to wrest control of the Brexit process and allow a series of "indicative votes" to explore alternative solutions to the government's deal. But there was no majority for any particular solution, other than an opposition to no-deal.
Theresa May's Brexit battles
Theresa May always struggled to keep the pro and anti-European wings of the Conservative Party on board with her Brexit plans.
Her doomed UK-EU divorce deal represented a compromise. But the blurring of several of her so-called "red lines" on the limits of EU power sparked fury within her divided Conservative Party. As negotiations with Brussels brought more UK concessions, a string of government resignations followed.
After the 2017 general election, which left the Tories severely weakened in parliament, hostility amid their own ranks to any moves towards a "softer" Brexit restricted May's room for manoeuvre.
Eurosceptics including the DUP strongly opposed her Brexit plan and the subsequent agreement, with many calling for the UK to leave the EU with no deal. In early 2019, the Tories in particular haemorrhaged support to the new hardline Brexit Party.
Equally, several pro-EU MPs also opposed a deal which, in their view, would leave the UK worse off than it had been inside the bloc. Some joined calls from opposition parties for a second referendum. Both the Conservatives and opposition Labour parties suffered defections of some MPs to a new pro-EU centrist party.
Amid the parliamentary deadlock, pressure from Tory Europhiles obliged the prime minister to open the door to a Brexit delay — and engage in cross-party talks, which collapsed after a few weeks.
Theresa May's fate was sealed after she revealed a fourth plan for getting her thrice-rejected Brexit deal through parliament. She tweaked the legislative package and crucially opened the door to a possible confirmatory referendum — a move which angered many in her party and sparked another government resignation.