Brexit (British Exit)

Brexit (British Exit) is a concept encompassing political, legal, and economic dimensions that describe the process of the United Kingdom (UK) leaving the European Union (EU). This process, initiated by a referendum held on 23 June 2016, is regarded as a turning point in the history of European integration. Article 50 of the Treaty on European Union (Lisbon Treaty) was activated for the first time in the Union’s history by a member state and culminated in the legal termination of the UK’s 47-year membership.^【1】

This departure carries meanings beyond a mere technical withdrawal from membership. The process serves as a historical case study of the clash between demands for national sovereignty and the dynamics of globalization and supranational integration. The UK’s desire to make its own laws, control its borders, and implement independent trade policies has generated uncertainty and a need for restructuring within Europe’s political architecture.^【2】

Historical Background

The relationship between the United Kingdom and European integration has followed a distant, pragmatic, and crisis-prone path from the outset. Britain’s reserved and skeptical stance toward continental European integration has led scholars to describe the country as an “Awkward Partner.”

Brexit Process (AA)

Accession to the EEC and the French Veto

In the aftermath of the Second World War, the UK initially did not participate in the European integration movements; instead, it positioned itself as a global power prioritizing its Commonwealth ties and its “Special Relationship” with the United States.^【3】 However, economic stagnation in Britain during the 1960s and the rapid growth of European Economic Community (EEC) countries forced the UK to reconsider its strategy.

The UK applied for membership twice: first in 1961 and again in 1967. Both applications were vetoed by French President Charles de Gaulle. De Gaulle argued that the UK did not align with the spirit of continental Europe, possessed an island mentality, and could serve as a political extension of the United States (a Trojan horse), thereby blocking its accession.^【4】 The UK only joined the Community after de Gaulle’s resignation, under the government of Edward Heath, on 1 January 1973.

Structural Differences Between the 1975 and 2016 Referendums

Britain’s conflict with Europe did not end with accession; debates intensified immediately afterward. Key structural differences explain why the outcome of the 1975 referendum diverged from that of the 2016 Brexit referendum.

In the 1975 referendum, the central debate focused on “economic welfare,” “advantages of the common market,” and “food prices”; in contrast, the 2016 referendum shifted the ground to “migration control,” “national identity,” and “sovereignty.”^【5】 In 1975, the Labour government, press, and business community largely reached a consensus in favor of “Remain”; in 2016, the Conservative Party was divided, and the media—particularly tabloid newspapers—strongly supported the Leave campaign.^【6】

Margaret Thatcher’s era marked a critical threshold. Her fierce negotiations over the UK’s contribution to the EU budget (“I want my money back”) and her 1988 Bruges Speech institutionalized Euroscepticism in Britain and normalized anti-EU sentiment within the Conservative Party base.^【7】

Legal Framework: The Lisbon Treaty and Article 50

The UK’s withdrawal process was conducted through Article 50 of the Lisbon Treaty, a mechanism previously untested under European Union (EU) law. Before the Lisbon Treaty entered into force in 2009, no treaty provision explicitly allowed a member state to leave the Union. Article 50 for the first time codified and legally grounded the right to “voluntary withdrawal.”

Nature and Operational Mechanism of Article 50

Article 50 of the Treaty on European Union (TEU) grants a member state the unilateral right to withdraw from the Union, while prescribing specific procedures to ensure the process proceeds in an orderly and rule-of-law-compliant manner. Its implementation consists of three key stages:

1. Notification: The member state must formally notify the European Council of its decision to withdraw, in accordance with its own constitutional requirements.^【8】
2. Negotiation: Following notification, negotiations begin between the EU and the departing state on a “Withdrawal Agreement.” This agreement addresses not only technical details of the exit—such as financial obligations, citizens’ rights, and border issues—but also outlines the framework for future relations.^【9】
3. Time Limit (Sunset Clause): Under Article 50(3), if no agreement is reached within two years from the date of notification, the EU Treaties automatically cease to apply to that state. This provision forms the legal basis for the greatest risk scenario: the “Cliff-edge” or “No-Deal Brexit.” Extension of the period is possible only with the unanimous consent of the EU Council.^【10】

Original Intent of Article 50 and the “Dictatorship” Admission

An ironic dimension of the Brexit process is the historical contrast between the intent behind drafting Article 50 and its actual use. Lord Kerr, the Scottish diplomat who authored the article, stated in an interview that when drafting it, he envisioned it being used not by a longstanding democracy like the UK, but by a totalitarian regime.

According to Lord Kerr, the article was designed to prevent chaos and impose discipline on the withdrawal process in the event of a dictatorial regime seizing power after a coup and deciding irrationally to leave. Kerr explicitly stated he “never imagined” the UK would invoke Article 50 and maintained that the process was intended to be reversible.^【11】

Domestic Legal Battle and the “Miller” Case

The process of triggering Article 50 in the UK transformed into a constitutional crisis between the Executive (Government) and the Legislature (Parliament). The government under Prime Minister Theresa May argued that it could invoke Article 50 using the “Royal Prerogative,” without parliamentary approval, as foreign affairs fall under executive authority.

However, this position was challenged in the Supreme Court, resulting in the landmark case R (Miller) v Secretary of State. The Court ruled that since EU law had conferred rights on individuals under UK domestic law, those rights could only be removed by an act of Parliament. This judgment stripped the government of its unilateral authority to proceed.^【12】

As a result of this judicial ruling, the government was compelled to seek parliamentary authorization and enacted the European Union (Notification of Withdrawal) Act 2017 to formally trigger Article 50.^【13】

Role and Consent Authority of the European Parliament

The withdrawal process is not solely determined by the member state’s initiative. Under EU law, while the European Commission leads negotiations, the final Withdrawal Agreement cannot enter into force without the consent of the European Parliament (EP). Although the EP does not directly intervene in the content of negotiations, it retains the authority to closely monitor the process, set red lines, and veto the final agreement. This forced the UK government to consider not only the Commission’s position but also the political sensitivities of the European Parliament.^【14】

The 2016 Referendum and the Dynamics of Withdrawal

The UK’s referendum on 23 June 2016 was not merely a political reflex but the culmination of years of political calculations, social anxieties, and identity crises. Prime Minister David Cameron, seeking to appease Eurosceptics within the Conservative Party and consolidate votes from the rapidly rising UK Independence Party (UKIP), delivered his famous “Bloomberg Speech” in 2013, pledging to hold a referendum on EU membership if re-elected. This move, described in political literature as a “big gamble,” failed to deliver the political stability Cameron anticipated and instead plunged the country into greater complexity.^【15】

Emotional Sovereignty Against Rational Economics

Voting Booths in the Referendum (AA)

The referendum campaign became a fierce and polarized rhetorical battle between two main camps: the "Britain Stronger in Europe" campaign advocating to remain in the EU, and the "Vote Leave" campaign advocating withdrawal.

• Remain Supporters: Their campaign strategy was largely based on rational economic arguments and risk analyses. Using data from the Treasury and the Bank of England, they argued that leaving the EU would shrink the UK economy, cause the pound to depreciate, reduce house prices, and generate commercial uncertainty. This strategy, labeled “Project Fear” by Leave campaigners, aimed to show voters scenarios of economic chaos.^【16】

• Leave Supporters: In contrast, the Leave campaign, led by Boris Johnson and Michael Gove, built its messaging around “emotional,” “nationalist,” and “sovereignty” themes. Their slogan, "Take Back Control", appealed to the British public’s desire to make their own laws, spend their own money (including the promise to redirect £350 million weekly to the NHS), and above all, control their own borders.

Migration and Border Control as Defining Factors

The most powerful sociopolitical dynamic determining the referendum outcome was migration. The issue was not merely demographic but central to debates on “national sovereignty” and “identity.” Public opinion polls showed that among reasons for voting to leave, “controlling the number of immigrants” ranked second at 34%, immediately after “making our own laws” at 49%.^【17】

The Leave campaign framed the EU’s core principle of “Free Movement” as a threat to the UK’s border security and social fabric. Particularly following the 2004 and 2007 enlargements, the influx of labor from Eastern European countries (Poland, Romania, Bulgaria) triggered fears among the British working class of “job losses,” “wage suppression,” and “collapse of the National Health Service (NHS).” Leave campaigners exploited these anxieties by arguing that as long as the UK remained in the EU, it could not decide who entered the country, as control lay with Brussels bureaucrats.^【18】

Fear Politics and Manipulation

The most manipulative dimension of the migration debate involved Turkey’s potential EU membership. The Vote Leave campaign used the claim that Turkey would soon become a full EU member and that millions of Turkish citizens would gain the right to free movement and migrate to the UK as propaganda material.

Campaign materials featured statements such as “Turkey (population 76 million) joins the EU,” accompanied by maps showing arrows pointing from Turkey’s borders with Syria and Iraq, creating the perception that instability and the refugee crisis in the Middle East would be channeled into the UK via Turkey. Academically, this is explained as the “securitization of migration”; migrants and refugees are removed from the realm of humanitarian concern and recoded as threats to social order, prosperity, and security.^【19】 This narrative resonated particularly in rural areas with high anti-migrant sentiment and in traditional Labour-voting industrial regions.

Results and a Divided Kingdom

When ballot boxes opened on the night of 23 June 2016, most polling firms were wrong. In a referendum with a record turnout of 72.2%, voters chose 51.9% for Leave and 48.1% for Remain. This result revealed deep geographic, demographic, and class divisions within the UK:

• Geographic Division: England (53.4%) and Wales (52.5%) supported leaving, while Scotland (62%) and Northern Ireland (55.8%) strongly voted to remain. This outcome triggered a new legitimacy crisis threatening the UK’s constitutional integrity, fueling demands for a second Scottish independence referendum and renewed discussions on a united Ireland.^【20】
• Demographic and Class Division: Seventy-three percent of voters aged 18–24 favored remaining in the EU, while 60% of voters aged 65 and over supported leaving. Similarly, university graduates largely voted “Remain,” while those with lower educational attainment voted “Leave.” Major metropolitan areas, especially London, with their cosmopolitan character, remained pro-EU, while deindustrialized northern towns and rural areas reactedively supported Brexit.^【21】

Negotiation Process, Political Crises, and the Transition Period

The public’s “Leave” vote initiated a diplomatic marathon and a series of government crises centered on determining how the UK would exit the EU. Following David Cameron’s resignation, Theresa May assumed the premiership with the slogan “Brexit means Brexit” and formally triggered Article 50 of the Lisbon Treaty on 29 March 2017, starting the two-year countdown.^【22】

Theresa May’s Term and Parliamentary Deadlock

At the outset of negotiations, the UK government adopted a hardline stance in its “Lancaster House Speech,” committing to leave the Single Market, exit the Customs Union, and end the jurisdiction of the European Court of Justice. However, May suffered a major strategic setback when she called a snap general election in 2017 to strengthen her negotiating position and lost her parliamentary majority. This result left the Conservative government dependent on the support of Northern Ireland’s Democratic Unionist Party (DUP), severely constraining its maneuverability.^【23】

The most critical impasse and the primary source of political crisis was the Irish border issue. The problem was this: if the UK left the Customs Union, a physical border (with customs checkpoints) would be required between the EU member state of the Republic of Ireland and Northern Ireland, part of UK territory. However, this would violate the 1998 Good Friday Agreement (Belfast Agreement), which ended conflict on the island of Ireland and threatened the peace process.^【24】

To resolve this, the EU and May’s government agreed on a mechanism called the “Backstop”. Under this arrangement, until a permanent solution was found, the entire UK would remain in the Customs Union, while Northern Ireland would be subject to stricter Single Market rules. However, this provision was rejected by hardline Brexiteers in the UK Parliament as a “trap” keeping the UK indefinitely within the EU orbit and as “subordination.” The result was a complete political deadlock: May’s Withdrawal Agreement was rejected by Parliament three times by record margins, forcing the Prime Minister to resign in May 2019.^【25】

Boris Johnson and the “Get Brexit Done” Strategy

Upon May’s resignation, Boris Johnson became Prime Minister in July 2019, adopting a more confrontational and risk-taking strategy. Johnson pressured the EU to revise the agreement by threatening a “No-Deal Brexit” and attempted to suspend Parliament (prorogation), pushing constitutional boundaries. His primary objective was to remove the controversial “Backstop” and replace it with the Northern Ireland Protocol. Under the new protocol:

• Northern Ireland remains legally within the UK customs territory.
• However, it continues to apply EU Single Market rules (on agriculture and product standards) in practice.
• Customs checks are conducted not on the island of Ireland but at ports between Great Britain and Northern Ireland (the Irish Sea).

Boris Johnson Signs Brexit Agreement (AA)

Although the DUP viewed this as a betrayal, Johnson won the December 2019 general election with the slogan “Get Brexit Done,” secured a parliamentary majority, and enacted the agreement into law.^【26】

Historic Moment: 31 January 2020 and the Transition Period

After three and a half years of political turmoil, the Withdrawal Agreement was approved, and the UK formally left the European Union on 31 January 2020 at 23:00 local time. However, this date marked a legal status change rather than a physical rupture. To avoid economic shock and commercial chaos, a “Transition Period” was implemented until 31 December 2020. During this period:

1. The UK exited EU decision-making bodies (Council, Parliament).
2. But it continued to comply with Single Market and Customs Union rules, contribute to the EU budget, and recognize the jurisdiction of the European Court of Justice.
3. This period granted both sides an 11-month limited timeframe to negotiate future trade relations.^【27】

Trade and Cooperation Agreement (TCA)

With only days remaining before the end of the transition period and the risk of a “cliff-edge” scenario looming, the parties reached agreement on the Trade and Cooperation Agreement (TCA) on 24 December 2020.

This agreement is the first “tariff-free and quota-free” trade deal signed between the EU and a third country. However, it largely excluded the services sector (particularly London’s financial hub, the City) and ended the free movement of goods, introducing non-tariff barriers such as rules of origin, health inspections, and customs declarations. This outcome confirmed the UK’s adoption of a “Hard Brexit” model.^【28】

Post-Brexit Economic Scenarios and Models

The UK’s decision to leave the EU is analyzed in economic literature as a case of “disintegration.” The central debate during the withdrawal process revolved around the trade-off between how much market access the UK would demand and how much national sovereignty (rule-making authority) it would insist upon. The UK government attempted to solve the difficult equation of preserving market access without conceding sovereignty.^【29】

Options on the Table: From the Norwegian Model to the Canadian Model

Throughout negotiations, the parties evaluated existing integration models to define the future relationship, but the UK’s “red lines” eliminated each option:

• Norwegian Model (European Economic Area - EEA): This model would have granted the UK full access to the Single Market without EU membership. Although it was the softest scenario, minimizing economic damage, it required continued free movement and acceptance of EU rules without a voice in their formulation (“fax democracy”), leading the government, which came to power on the promise of “Take Back Control,” to reject it.^【30】
• Swiss Model (Bilateral Agreements): This model, involving hundreds of sector-specific bilateral agreements, was deemed unmanageable, unsustainable, and overly complex (“cherry-picking”) by the EU.
• WTO Rules (No-Deal Brexit): Referred to as the “worst-case scenario,” this model would have subjected UK-EU trade to the World Trade Organization’s “Most Favored Nation” tariffs. The reintroduction of high tariffs on sectors such as automotive, agriculture, and textiles, and the disruption of supply chains, made this option a last-resort fallback due to intense business pressure.^【31】

Ultimately, the UK opted for the Canadian Model, adapted into the more comprehensive Trade and Cooperation Agreement (TCA) due to geographical proximity. While this model eliminated tariffs and quotas, it reintroduced non-tariff barriers such as bureaucracy, rules of origin, and plant health inspections.

Brexit During the Pandemic

The largest factor complicating the isolation and measurement of Brexit’s economic effects was the coincidence of the transition period’s end (31 December 2020) with the global COVID-19 pandemic. This created what scholars term a “perfect storm” of multiple shocks for the UK economy.

The pandemic both deepened and masked the structural problems caused by Brexit:

1. Supply Chain Disruptions: The combination of border bureaucracy, pandemic-related quarantines, and global logistics crises caused severe disruptions in supply chains.
2. Labor Shortage Crisis: The end of free movement led thousands of EU nationals working in logistics (truck drivers), agriculture, and healthcare to leave the UK. As the economy reopened after the pandemic, the labor gap resulted in crises such as fuel shortages at petrol stations and empty supermarket shelves.^【32】

Macroeconomic Effects: Growth, Investment, and the Financial Center

In the post-exit period, the UK economy has experienced a slower recovery compared to other G7 countries. Although the pound’s depreciation theoretically supported exports, it increased import costs for intermediate goods, fueling inflation. Uncertainty caused “business investment” to stagnate since the 2016 referendum, leading to underperformance relative to potential growth.^【33】

Moreover, London’s status as a global financial center (the City) has been affected. The exclusion of financial services from the TCA (loss of passporting rights) has led to the relocation of trillions of dollars in assets and operational hubs from London to EU-based centers such as Dublin, Frankfurt, Paris, and Amsterdam.^【34】

Implications for Türkiye–United Kingdom Relations

Historically, the United Kingdom has been one of the countries supporting Türkiye’s integration with the West and its accession to the European Union (EU). Therefore, Brexit represents for Ankara not only a risk of losing a commercial market but also a geopolitical shift: the loss of a key ally (“strategic lever”) advocating Türkiye’s position at the Brussels table.^【35】

Customs Union Closure and the Risk of “Unauthorized Negotiation”

The Brexit process created major uncertainty for the Turkish economy. The root cause lies in the asymmetric structure of Türkiye’s Customs Union with the EU (Council Decision 1/95). Under Customs Union rules, Türkiye must adopt the EU’s common trade policy toward third countries; however, Türkiye lacks the authority to independently negotiate Free Trade Agreements (FTAs) with any country unless the EU has already concluded an agreement with that country.^【36】

This legal constraint has placed Türkiye in a diplomatic “trap”:

• As the UK exits the Customs Union (and thus the Common External Tariff), it is now obligated to apply tariffs on Turkish goods.
• Türkiye, however, could not legally sign its own agreement with the UK until the EU-UK trade deal was finalized.
• Had the EU and UK failed to reach an agreement by 31 December 2020 (a No-Deal Brexit), Türkiye would have faced customs barriers in its second-largest export market, risking an annual export loss of up to $2.4 billion according to Ministry of Trade data. This scenario posed a vital threat to Türkiye’s automotive, white goods, and textile sectors.^【37】

Shadow Negotiations and the 29 December 2020 Free Trade Agreement

Turkish diplomacy tracked the process through “shadow negotiations” with the UK, parallel to EU-UK talks, to manage this risk. The anticipated relief came when the EU and UK reached an agreement on 24 December. Immediately thereafter, on 29 December 2020, Türkiye and the UK signed a historic Free Trade Agreement (FTA).

According to official data from the Ministry of Trade, the scope and significance of this agreement are as follows:

1. Continuation of the Customs Union: The zero-tariff regime for industrial goods was preserved, preventing supply chain disruptions. This eliminated the costs that would have arisen under a No-Deal scenario.
2. Agriculture and Services: Existing tariff quotas for agricultural products were maintained. However, “deep FTA” elements such as services, public procurement, and e-commerce were not fully included at first; their future negotiation was agreed upon.
3. Historical Significance: This agreement is recorded as the most significant trade deal Türkiye has signed since the Customs Union.^【38】

Free Trade Agreement Signed Between Türkiye and the United Kingdom (AA)

Strategic Partnership and Defense Industry Cooperation

The post-Brexit period has strengthened the potential for closer ties between Türkiye and the UK. Both countries, positioned on the periphery of Europe, share a similar political stance: valuing the EU market while maintaining distance from Brussels’s political integration. This geopolitical alignment has created a foundation for elevating bilateral relations to a “strategic partnership” level, particularly in defense industry, security, and counterterrorism.

Notably, negotiations between Türkiye’s national fighter jet project (TF-X) and British engine manufacturer Rolls-Royce and defense giant BAE Systems are among the most concrete indicators of this new era.^【39】 However, academic analyses warn that this rapprochement must not weaken Türkiye’s EU accession aspirations. Relations with the UK are envisioned as complementary to, not a substitute for, EU membership.^【40】

The Future of European Integration and the United Kingdom

Brexit is not a simple deviation (anomaly) in the history of European integration but a structural “earthquake” that has altered Europe’s political architecture. The process has shattered the entrenched myth that “leaving the Union is impossible,” demonstrating that integration is not an inevitably linear process but one that can be reversed.^【41】

Enlargement Fatigue and Consolidation

The Brexit process pushed the EU inward, compelling it to question its own structure. Immediately after the referendum, EU leaders perceived the UK’s departure as an existential threat that could trigger a “domino effect,” leading other members to leave (Frexit, Nexit, etc.). In response, Brussels adopted an uncompromising stance during negotiations to make the cost of leaving tangible and preserve Union unity.

This strategy succeeded in the short term, creating a sense of political cohesion within the EU-27 bloc. However, Brexit’s most tangible and lasting impact has been on its Enlargement Policy. The Union has shifted toward a more cautious approach toward candidate countries such as the Western Balkans and Türkiye, prioritizing “absorption capacity” over geographical expansion and focusing instead on “deepening” integration among existing members. The UK’s departure has damaged the EU’s claim to be a “magnet” and rekindled debates over a “multi-speed Europe.”^【42】

The UK’s Future Vision: “Global Britain”

Post-exit, the UK’s core strategy has been built on the vision of “Global Britain”. This vision aims to free the UK from the restrictive regulatory chains of the EU and transform it into a global trading power through free trade agreements with former Commonwealth countries, the United States, and rising Asian economies.

However, this vision faces significant structural obstacles. According to the international trade “gravity model,” geographical proximity is the most important determinant of trade volume. Protectionist policies by major economies such as the US and China, combined with geographical distance, make it difficult for the UK to replace the EU market, which offers both proximity and scale. Thus, while regaining political sovereignty, the UK risks losing economic influence.^【43】

Threat to Internal Unity and Final Outcome

The Brexit process is not yet complete; for while the external struggle for sovereignty has been resolved, it has triggered an internal crisis of unity. Rising demands for a second Scottish independence referendum, fueled by opposition to Brexit, and the accelerated economic integration of Northern Ireland with the Republic of Ireland due to its de facto continued access to the EU market, are the greatest threats to the political integrity of the “United Kingdom.” In managing its exit from the EU, the UK now finds itself in a struggle to preserve its own unity.^【44】

Ultimately, Brexit has neither created the “freedom paradise” promised to the UK nor brought about the “collapse” of the EU. The resulting reality is a lose-lose scenario in which both sides have lost power, yet remain bound by mutual dependencies (economic, security, intelligence, energy), leading to a new, complex, and distant relationship model based on continuous negotiation.^【45】