EU law and the balance of competences: A short guide and glossary

This guide explains key elements of EU law and their history. It accompanies the detailed guide 'Review of the balance of competences'.


The Government is carrying out a Review of the balance of competences between the European Union and the United Kingdom. The review is an audit of what the EU does and how it affects the UK. This document is a guide to key elements of EU law, for reference in relation to the review.

Short guide

The European Union, which succeeded the European Community, was established by the EU Treaties – see further below. The parties to the treaties are the Member States of the EU – currently there are 28 Member States including the UK. Under the treaties the Member States confer competences on the EU – such as the power to adopt legislation. The EU can only act within the limits of its competences.

The EU has a number of institutions, such as the European Council, the Council of Ministers, the European Commission and the European Parliament. Acting together or separately, these institutions pass laws (such as regulations, directives or decisions), which may take effect automatically in the UK’s legal systems or require the UK to pass national legislation to give effect to the EU laws. The UK may also be affected by the treaties themselves, which may restrict what the UK can do, for example, restricting the UK’s power to limit imports from other Member States.

The Court of Justice of the European Union interprets the treaties and the laws which the EU passes and decides if Member States have abided by them.

There are two key EU treaties, which have been amended several times. They are the Treaty on the European Union (‘TEU’, originally the Maastricht Treaty), and the Treaty on the Functioning of the European Union (‘TFEU’, originally called the Treaty of Rome). The treaties are effective in the UK by virtue of the European Communities Act 1972, as amended.


The European Economic Community was established in 1957 by the Treaty of Rome, and became the European Community (EC) in 1967. The Treaty of Rome gave the Community a number of tasks including establishing a common market and progressively approximating the economic policies of the Member States. The United Kingdom joined the Community in 1973, and confirmed that decision in a UK-wide referendum in 1975.

In 1986, the Single European Act made further provision for the establishment of the common market, now referred to as the ‘internal market’, and defined as an area without internal frontiers, in which the free movement of goods, persons, services and capital is ensured. The Single Market Act also added a number of new policy areas to the Community’s competence, including, for example, a specific environmental competence. . The Maastricht Treaty followed in 1993. This treaty established the European Union, which had a three pillar structure, with the European Community being the first pillar, the common foreign and security policy the second pillar and justice and home affairs (covering immigration and asylum, civil judicial cooperation and police and judicial cooperation in criminal matters) the third pillar. Further changes were made by the Treaty of Amsterdam (1997) and the Treaty of Nice (2000), including to the competences of the Union.

The EU entered a period of expansion, reaching 28 Member States by 2013. This prompted calls for a new Treaty. After long discussion, the Lisbon treaty was signed in 2007. This treaty renamed and amended the original treaties, collapsed the three pillar system into a single European Union, and incorporated the Charter of Fundamental Rights into the EU Treaties.


Term Definition
Acquis Also known as the ‘acquis communautaire’: the combined law of the EU, as expressed through the Treaties, Regulations, Directives, Decisions, Delegated Acts, Implementing Acts, and the case law of the Court of Justice. New Member States must sign up to the EU acquis currently in force when they join the EU.
Co-decision procedure Now the ordinary legislative procedure.
Competence For the purposes of this review, we are using a broad definition of competence. Competence in this context is about everything deriving from EU law that affects what happens in the UK. That means examining all the areas where the Treaties give the EU competence to act, including the provisions in the Treaties giving the EU institutions the power to legislate, to adopt non-legislative acts, or to take any other sort of action. But it also means examining areas where the Treaties apply directly to the Member States without needing any further action by the EU institutions. The EU’s competences are set out in the EU Treaties, which provide the basis for any actions the EU institutions take. The EU can only act within the limits of the competences conferred on it by the Treaties, and where the Treaties do not confer competences on the EU they remain with the Member States. [Article 5(2) TEU]
Exclusive Competence Areas in which only the EU can adopt legal acts. [Articles 2(1) and 3 TFEU]
Shared Competence Areas in which either the EU or Member States can adopt legal acts. To the extent that the EU exercises its shared competence, the Member States are not free to exercise their competence, but may do so again once the EU ceases to exercise the competence (for example, by repealing a legislative act without replacing it). [Articles 2(2) and 4 TFEU]
Parallel Competence Areas where the EU has competence to carry out activities and conduct a common policy, but the Member States can exercise competence as well. The EU’s and Member States’ policy in these areas “should complement and reinforce each other”. Parallel competence is basically the same as supporting competence. [Articles 4(3) and (4) TFEU.]
Supporting Competence Areas in which both the EU and the Member States may act, such as culture, tourism and education. Action by the EU does not prevent the Member States from taking action of their own and the Treaties explicitly prohibit harmonisation of laws. [Articles 2(5) and 6 TFEU.]
Charter of Fundamental Rights The Charter of Fundamental Rights consolidates in a single document the fundamental rights applicable at the European Union (EU) level. It establishes ethical principles and rights for EU citizens and residents that relate to dignity, liberty, equality, solidarity, citizenship and justice. While the European Convention on Human Rights (ECHR) is limited to protecting civil and political rights, the Charter goes further to cover workers’ social rights, data protection, bioethics and the right to good administration. The Charter does not extend the competences of the Union beyond those already granted in the Treaties and only applies to Member States when they are implementing EU law. [Article 6 TEU]
Council of Europe A different organisation from the EU, with 47 member states (as opposed to the EU’s 27). Founded in 1949, the Council of Europe aims to achieve greater unity between its members through discussion and action in relation to a broad range of areas of common concern. The best known agreement of the Council of Europe is the European Convention on Human Rights.
Council of Ministers The Council of the European Union (“Council of Ministers” or “Council”), along with the European Council, is the Union’s main policy-making body. It also, jointly with the European Parliament, exercises legislative and budgetary functions. Its meetings are attended by Member State ministers, and it is thus the institution which, along with the European Council, represents the Member States. The Council meets in different configurations, bringing together different Member State ministers depending upon the issue at hand. For instance, Council meetings on Education are attended by the Secretary of State for Education. [Article 16 TEU and Articles 237 to 243 TFEU]
Court of Justice of the European Union The CJEU has jurisdiction to rule on the interpretation and application of the Treaties. In particular, the Court has jurisdiction to rule on challenges to the validity of EU acts, in infraction proceedings brought by the Commission against Member States and on references from national courts concerning the interpretation of EU acts. The Court is made up of three sub-courts: the General Court, the Civil Service Tribunal (which hears cases about EU staff members) and the Court of Justice (which is sometimes called the ECJ). [Article 19 TEU and Articles 251 to 281 TFEU]
Decisions A legislative act of the EU which is binding upon those to whom it is addressed. If a decision has no addressees, it binds everyone. [Article 288 TFEU]
Delegated Acts A form of EU secondary legislation. A legislative act, such as a Directive or a Regulation, can delegate power to the Commission to adopt delegated acts to supplement or amend non-essential elements of the legislative act. [Article 290 TFEU]
Directive A legislative act of the EU which requires Member States to achieve a particular result without dictating the means of achieving that result. Directives must be transposed into national law using domestic legislation, in contrast to Regulations, which are enforceable as law in their own right. [Article 288 TFEU]
Enhanced Cooperation Enhanced cooperation is where a group of Member States act under the treaties in an area where there is not sufficient support to adopt legislation binding on all Member States. The Council must authorise the enhanced cooperation and there must be at least 9 participating Member States. Acts adopted under the enhanced cooperation arrangements only bind the participating Member States and must comply with a number of safeguards, including not undermining the internal market. . Enhanced cooperation cannot extend the powers of the EU, or apply to areas that fall within the EU’s exclusive competence. [Article 20 TEU and Articles 326 to 334 TFEU]
European Commission The Commission is the main executive body of the EU. It has general executive and management functions. In most cases it has the sole right to propose EU legislation. In many areas it negotiates international agreements on behalf of the EU and represents the EU in international organisations. And the Commission also oversees and enforces the application of Union law, in particular by initiating infraction proceedings where it considers that a Member State has not complied with its EU obligations. [Article 17 TFEU and Articles 244 to 250 TFEU]
European Convention on Human Rights An international convention, ratified by the United Kingdom and incorporated into UK law in the Human Rights Act 1998. It specifies a list of protected Human Rights, and establishes a Court (European Court of Human Rights sitting in Strasbourg) to determine breaches of those rights. All Member States are parties to the Convention. The Convention is a Council of Europe Convention, which is a different organisation from the EU. Article 6 TEU provides for the EU to accede to the ECHR.
European Council The European Council defines the general political direction and priorities of the EU. It consists of the Heads of State or Government of the Member States, together with its President and the President of the Commission. [Article 15 TEU and Articles 235 and 236 TFEU]
European Parliament The European Parliament (EP) consists of representatives elected by Union citizens. The EP shares legislative and budgetary power with the Council, and has oversight over the actions of the Commission. [Article 14 TEU and Articles 223 to 234 TFEU]
External Competence The capacity of the EU to act internationally on its own behalf, including by concluding or being a party to international agreements with third countries. This can only be done in areas where the EU has competence under the Treaties (namely, where it has exclusive, shared, parallel or supporting competence). [Articles 216 to 219 TFEU]
The EU Treaties (including TEU and TFEU) The European Economic Community (EEC) was established by the Treaty of Rome in 1957. This Treaty has since been amended and supplemented by a series of Treaties, the latest of which is the Treaty of Lisbon.The Treaty of Lisbon, which entered into force on 1 December 2009, re-organised the two Treaties on which the European Union is founded: the Treaty of the European Union (TEU) and the European Community Treaty, which was re-named the Treaty on the Functioning of the European Union (TFEU).
Harmonisation The introduction of common standards and laws throughout the Member States of the EU.
Implementing Acts A form of EU secondary legislation. EU legislation can confer powers on the Commission (or in some cases, on the Council) to adopt implementing acts. Implementing Acts are used to ensure uniform implementation of the conferring legislative act across the EU. [Article 291 TFEU]
Internal Market The internal market of the European Union is an area without internal frontiers in which the free movement of goods, persons, services and capital is ensured. [See, in particular, Articles 26 to 66 and 114 to 118 TFEU]
Legal Base An Article in the Treaties which gives the EU competence to adopt a legal act.
Ordinary legislative procedure The legislative procedure consisting of the joint adoption by the European Parliament and the Council of a regulation, directive or decision on a proposal from the Commission. The Council can generally act by qualified majority voting. This is the most common procedure for adopting regulations, directives and decisions. The relevant legal base in TFEU will determine whether this procedure applies. [Articles 289(1) and 294 TFEU]
Proportionality EU action must comply with the principle of proportionality. Under this principle action undertaken by the EU should not exceed what is necessary to achieve the objectives of the Treaties. [Article 5(4) TEU]
Qualified Majority Voting Where only a specified majority of votes is required in the Council for the Council to act and the share of votes of each Member State reflects its population size. Where the treaties provided for a measures to be adopted by the Council on the basis of qualified majority voting it means that no single Member State can block the adoption of the measure – there is no national veto. [Article 16 TFEU and Article 3 of Protocol (No 36 on Transitional Provisions]
Regulation A legislative act of the EU which is directly applicable in Member States without the need for national implementing legislation. (as opposed to a Directive, which must be transposed into national law by Member States using domestic legislation)[Article 288 TFEU]
Special legislative procedure The legislative procedure consisting of the adoption of a regulation, directive or decision by the European Parliament or the Council. In these cases the legislation is not adopted jointly by the European Parliament and the Council. The relevant legal base in TFEU will determine whether this procedure applies. An example of when the special legislative procedure is used can be found in Article 352 TFEU, which provides that the Council can adopt legislation acting unanimously on a proposal from the Commission and after obtaining the consent of the European Parliament. [Article 289(2) TFEU].
State Aids Advantages conferred on a selective basis to undertakings by national public authorities. In certain circumstances these will be justified, but in other cases they will form an unlawful anti-competitive practice. [Articles 107 to 109 TFEU]
Subsidiarity EU action must comply with the principle of subsidiarity. Under this principle, outside of areas of exclusive EU competence, the Union shall act only if and insofar as the objectives of the proposed action cannot be sufficiently achieved by the Member States at national, regional or local level. [Article 5(3) TEU]
Third Country The term used for a non-Member State.
Unanimity Where the Council can only act with the approval of all Member States (in contrast to Qualified Majority Voting, where some Member States can oppose a measure, and it can still pass).
Published 12 December 2012
Last updated 21 March 2013 + show all updates
  1. Update to glossary.

  2. First published.