The United Kingdom joined what was then the European Economic Community on 1 January 1973, beginning a relationship that would last for more than four decades. This timeline shaped trade, law, and movement between the UK and European countries, setting the stage for later debates about sovereignty and alignment.
Brexit in 2020 formally ended membership, but the practical legacy continues to influence policy, market access, and political discourse across the UK and Europe.
| Status | Start Date | End Date | Key Event |
|---|---|---|---|
| Application submitted | 1967 | UK submits first formal application to join the EEC | |
| Membership begins | 1 January 1973 | UK becomes an EC member alongside Ireland and Denmark | |
| Referendum confirms membership | 5 June 1975 | 67% of voters support continued EC membership | |
| Negotiation of exit terms | 2017 | 31 January 2020 | Article 50 triggered; transition period begins |
| Full withdrawal completed | 1 February 2020 | Transition period arrangements under TCA apply from 1 January 2021 |
Accession Negotiations and Conditions
Meeting the Copenhagen Criteria Before Joining
Before the UK could join the EC in 1973, it had to align domestic regulations with common standards on agriculture, competition, and governance. British leaders framed membership as a way to modernize industries and deepen ties with neighboring economies.
Political Context in the 1960s and 1970s
Diplomatic shifts during the Cold War and changing Commonwealth relations influenced how the UK approached European integration, with debates over sovereignty balancing against economic opportunity.
Economic and Trade Impact During Membership
Tariff Reductions and Market Access Gains
As a member, UK businesses enjoyed reduced tariffs on exports to the Single Market, while imports from the EU benefited from streamlined customs procedures and shared standards.
Sector-Specific Changes in Key Industries
Financial services, manufacturing, and agriculture restructured to comply with EU rules on state aid, environmental protection, and worker rights, reshaping supply chains across the UK and Europe.
Legal Harmonization and Regulatory Alignment
Adoption of EU Law Into Domestic Legislation
Directives on environmental protection, consumer rights, and competition policy became part of UK statute books, influencing how regulators operated across multiple sectors.
European Court of Justice Jurisdiction
While a member, UK courts could refer questions to the ECJ and were bound by its rulings in areas such as free movement and cross-border dispute resolution.
Political Shifts and Public Opinion Over Time
From Consensus to Division in Political Parties
Initial cross-party support for the EC evolved into sharp divisions, influencing campaigns, leadership contests, and the broader policy landscape around sovereignty and immigration.
Generational and Regional Differences in Voting Patterns
Demographic changes and local economic conditions contributed to varying levels of support for EU membership, setting the stage for later referendum outcomes.
Key Takeaways for Understanding UK EU Relations
- Membership began formally on 1 January 1973 and lasted until 31 January 2020.
- A 1975 referendum confirmed public support for staying in the European Communities.
- Negotiations focused on budget contributions, fishing rights, and regulatory alignment.
- The transition arrangement preserved many market-access benefits until the end of 2020.
- Future relationship depends on policy alignment, political will, and continued public support.
FAQ
Reader questions
When did the UK first vote to stay in the European Communities?
The 1975 referendum asked voters whether the UK should remain a member of the European Communities, and 67% supported continued membership.
How long was the transition period after Brexit was triggered?
The transition period ran from 1 February 2020 to 31 December 2020, during which EU rules largely still applied while future arrangements were negotiated.
What changed for businesses at the end of 2020?
From 1 January 2021, new customs checks, regulatory barriers, and rules on services reduced seamless market access between the UK and EU.
Can the UK rejoin the EU in the future?
Rejoining would require unanimous agreement from existing member states and meeting the same Copenhagen criteria, along with a new referendum in the UK.