4.3 - The European Union and post-exit policy making

EU aims and institutions

The European Union (EU) is a political and economic union of European states, with 27 members as checked on 2 October 2026. Cooperation developed partly to reduce conflict and strengthen economic links. Its aims include peace, prosperity, rights, sustainable development and closer cooperation, as well as a single market and economic and monetary union. These are aims against which performance should be judged, not proof that all have already been achieved. EU aims and membership facts.

Treaties establish the EU's powers and decision-making rules. Supranational arrangements give shared institutions authority to make or enforce decisions beyond one national government; intergovernmental arrangements depend more directly on cooperation between member governments. The EU combines these approaches. Its powers come from treaties agreed by its members, rather than a general right to legislate on everything.

In much EU law-making, the European Commission proposes legislation, while the elected European Parliament and the Council of the European Union, representing national ministers, agree the law. The European Council, consisting of national leaders, sets broad political direction. It is distinct from the Council of the European Union. The Court of Justice of the European Union (CJEU) interprets EU law and supports consistent application. Institutional roles.

Shared rules can prevent one state discriminating against another's products, while collective negotiation gives member states more bargaining weight. This is pooled sovereignty: governments accept some constraints on independent choice in return for influence over joint decisions and benefits from cooperation. A supporter argues that acting jointly increases effective power. A critic argues that a national government may be bound by a decision it opposed, weakening direct national control. Both claims identify consequences of the same institutional arrangement.

The UK participated in these institutions while a member. It left on 31 January 2020 and ceased taking part in their ordinary political decision-making as a member. Departure therefore changed both obligations and opportunities to influence shared policy. The institutions' roles still matter because EU rules affect the UK through trade and specific post-exit agreements.

Four freedoms and the single market

The single market aims to let economic activity cross national borders within a common regulatory framework.

These freedoms complement each other. A firm may sell goods across a border, invest capital in a branch, employ mobile workers and purchase services from another state. Removing only the tariff would leave many barriers to that connected activity. The EU's customs union also applies a common external tariff to imports from outside; a customs union and the wider single market are related but distinct arrangements.

Achievement is substantial but incomplete. The single market began in 1993 and has created legally enforceable cross-border opportunities. Yet the Council itself identifies remaining barriers, especially in services and capital markets. Its 2026 One Europe, One Market agenda seeks further removal of barriers. An institution's reform programme is evidence that work remains; it does not establish that earlier integration achieved nothing. Council single-market account and 2026 reform agenda, checked 2 October 2026.

Free movement of people should not be confused with Schengen, the separate arrangement removing many routine internal border checks. Membership and participation do not coincide perfectly. Rights to work or reside and the arrangements for checking someone at a border are different questions.

Economic and political union

The EU's wider union aims go beyond removing obstacles to individual transactions, but integration has proceeded unevenly.

Economic union involves linking economies through shared market rules and coordination of economic policy. Monetary union adds a common currency and monetary policy for participating states. The euro reduces exchange-rate uncertainty between its users, and the European Central Bank sets monetary policy for the euro area. Member governments still make many taxation and spending decisions, within common rules and commitments. Economic integration therefore does not mean a single government sets every member state's budget. Commission explanation of economic and monetary union.

As checked on 2 October 2026, 21 of the 27 EU members use the euro. The UK retained sterling throughout its membership. A common currency is a major achievement for its participating states, yet the different membership of the euro area and EU demonstrates differentiated integration. A single interest-rate policy may also fit some economies better than others, making common policy and national circumstances a source of tension. EU countries and the euro.

Political union concerns stronger common institutions, collective decision-making and cooperation on political matters. An elected European Parliament and binding shared legislation demonstrate real integration. Member governments also cooperate on external affairs and security. However, the EU has not become one sovereign state replacing all its members. National governments retain important powers, national elections remain consequential, and areas requiring agreement among governments limit a single collective response.