How Brexit Happened – Why Did the UK Leave the EU? Here’s the Full Story

What Is Brexit?

The word Brexit is a portmanteau of the words British and exit, referring to Britain’s exit from the European Union. The EU is a political and economic union of 27 nations that are linked by common regulations on matters such as trade, migration, security, and policies. The UK had joined the union in 1973, but from that time, endless debate had been going on about sovereignty, immigration, and economic control, which lays the groundwork for an eventual departure.

The issue reached a tipping point in a referendum of 2016 where British voters were asked: “Should the United Kingdom remain a member of the European Union, or leave the European Union?” Result came back with 52 percent voting to leave and 48 percent voting to remain.

Timeline of Major Events in Brexit

The chronicles of Brexit span several decades, with decisive moments shaping the United Kingdom’s relations with Europe. Knowledge of these milestones will bring clarity to how the decision to leave the European Union took shape, as well as insights into the maze of processes following it. Sitting below are the landmark instances signifying this voyage.

1973 – UK Joins EEC

Under Conservative Prime Minister Edward Heath, United Kingdom joins the European Economic Community (EEC), the forerunner of the EU.

1992 – Maastricht Treaty

The EEC formally became the European Union. Although the UK signed the treaty, it opted out of several provisions, like the euro currency.

23 June 2016 – Brexit Referendum

The referendum was held under the auspices of the Cameron government to fulfill a Conservative manifesto pledge. Leaving won by a narrow margin, and Cameron accordingly tendered his resignation.

29 March 2017 – Notification Under Article 50 Is Made

Under PM Theresa May, the UK gave formal notice of its intention to leave the EU, starting a two-year negotiation period.

29 March 2019 – Original Brexit deadline missed

With Parliament repeatedly rejecting May’s deal, it was delayed multiple times, bringing about May’s resignation.

24 July 2019 – Boris Johnson becomes PM

Johnson promised to “get Brexit done” and renegotiated parts of the deal.

31 January 2020 – UK leaves the EU

Brexit was “done” at last, albeit a transition phase lasting 11 months then began.

31 December 2020 – End of transition

Having entered into a new trade agreement barely days before the deadline, the UK finally exited the EU single market and customs union, hence commencing the post-Brexit era.

Why Did People Vote Leave?

• Sovereignty: The majority held the view that EU laws and courts impinged on the UK governing itself.
• Immigration: The rules on free movement allowed citizens from member states to reside in the UK, which some voters considered uncontrolled.
• Cost of membership: Being a net contributor to the EU budget, the UK was seen by some as being fleeced.
• Democratic accountability: EU institutions were said by critics to be distant and without any direct way to be held accountable by British voters.

The Leave campaign seized on these themes with slogans like “Take Back Control,” appealing to concepts of pride and sovereignty.

Why Did People Vote Remain?

• Economic certainty: Businesses warned that leaving the single market would be detrimental to trade and investment.
• World power: The UK’s voice in international affairs was stronger while still part of the EU.
• Freedom of movement: Those who placed great value on the ability to live, work, and travel freely within the EU.
• Peace and cooperation: EU membership was also viewed as part of the post-war commitment to European peace and shared institutions.

The Remain campaign seemingly was never able to enact a simple, emotive message, relying instead too much on the economic risks of leaving: a hard sales job that few undecided voters accepted.

Key Politicians and Political Changes

Several key politicians were instrumental throughout the entire phase of the Brexit issue in stimulating and later deciding its outcomes. Their decisions, styles of leadership, and political fortunes were tightly leashed to the ebb and flow of opinion in public and in Parliament over the question of UK membership of the EU. We now see a few of the most important people that shaped this phase.

David Cameron (Conservative PM, 2010–2016)

Called the referendum and supported Remain. Resigned on the implementation of the Leave vote.

Theresa May (PM, 2016–2019)

Attempted to enact Brexit via a compromise deal, but was undermined by internal party dissent. Her deal got defeated thrice.

Boris Johnson (PM, 2019–2022)

Ran the Leave campaign; came back into politics as a defender of Brexit. The 2019 majority election win cleared the path to Brexit.

Nigel Farage (UKIP, later European Research Party)

Such a seasoned Eurosceptic pushed hard for the referendum. Though he was never an MP, his clout was significant in the debate.

Keir Starmer (Leader of the Labour Party 2020-present)

Initially a supporter of a second referendum, he was now accepting Brexit as a fact and working on how to make it work.

Brexit ripped apart the mainstream parties in a way never seen before, with leadership upheavals, rebellions at home, and dashed hopes of a pro-EU centrist Liberal Democrats.

Parliamentary Battles and Legal Challenges

The post-referendum years were marked by legislative gridlock. Theresa May was unable to hold together the majority of MPs for the negotiated deal. It faced multiple votes in Parliament to reject proposed arrangements, block a scenario of “no-deal” Brexit, and delay the date of withdrawal.

Courts also intervened. The UK Supreme Court held that Parliament had to give its authorisation for the triggering of Article 50, and later that the suspension of Parliament by Boris Johnson in 2019 was unlawful.

These somewhat legal and political battles served to highlight that Brexit went beyond splitting the British public; it divided the constitutional framework of the United Kingdom.

The Final Deal and What it Covers

• Zero tariffs and quota-free trade in goods, with new customs checks and paperwork added.
• No access to the single market or customs union—for services, this mainly hits finance.
• End of free movement between UK and EU.
• Joint governance structures to resolve disputes.

Cooperation takes place on security, data sharing, and law enforcement, but with the UK having lesser access to EU databases. The deal was finally settled, yet much friction remains, especially regarding Northern Ireland and regulatory divergence.

The Northern Ireland Protocol

Among the most complicated of all the Brexit issues was that of the Irish border. To prevent a hard border between NI and the Republic of Ireland, a special arrangement—the Northern Ireland Protocol—was agreed upon by both sides.

By this construction, Northern Ireland remained in alignment with some EU rules in order to keep the land border open, while checks and controls are set up in the sea route between Great Britain and Northern Ireland. This generated disruption to trade and political unrest, predominantly among the unionists.

It was later agreed upon between the UK and EU to adopt the Windsor Framework in 2023 to ease the checks and calm tensions; however, the political sensitivity remains.

The Economic Impact of Brexit

• Trade: Trade flows between the UK and EU dropped immediately after Brexit but have now started to recover. Higher Customs charges and delays form hindrances for the businessmen.
• Labour: Industries such as agriculture, hospitality, and health have faced labour shortages ever since the free movement ended.
• Investment: Given the high uncertainty, foreign direct investment in the UK diminished in the years following the referendum.
• Inflation and GDP: Most analysts would agree that slower growth and higher inflation compared to peers have been some consequences of Brexit.

There are arguments suggesting that Brexit allows for flexible trade deals and regulatory innovation, but in practice economic benefits have been few and far between.

Summary

The biggest and most historic political decision in modern UK history was Brexit. In so doing, it is remoulding the country’s relation with Europe, setting off deep political and social divisions, and subjecting the Constitution to a stress test. That is to say, while referendum might be over, and actual arguments and effects will never be.