Preliminary ruling

If a court or tribunal of a Member State finds a provision of EU law to be ambiguous, equivocal or unclear, it may seek a preliminary ruling; and if that court or tribunal is one from which there is no appeal, the court must make an application. In either case, the domestic court be adjourned until the ECJ ruling is issued. The question to the ECJ must be short and succinct, but may be accompanied by documents explaining the context and circumstances of the issue. The ECJ may decline to give judgement in the absence of a genuine dispute, on the basis that it will not consider "moot points".[3]

Article 267 of the Treaty on the Functioning of the European Union provides:

The Court of Justice of the European Union shall have jurisdiction to give preliminary rulings concerning:

• (a) the interpretation of the Treaties;
• (b) the validity and interpretation of acts of the institutions, bodies, offices or agencies of the Union;

Where such a question is raised before any court or tribunal of a Member State, that court or tribunal may, if it considers that a decision on the question is necessary to enable it to give judgment, request the Court to give a ruling thereon.

Where any such question is raised in a case pending before a court or tribunal of a Member State against whose decisions there is no judicial remedy under national law, that court or tribunal shall bring the matter before the Court.

If such a question is raised in a case pending before a court or tribunal of a Member State with regard to a person in custody, the Court of Justice of the European Union shall act with the minimum of delay.[4]

What constitutes a "court or tribunal" is a matter of Union law and it is not to be determined by reference to national law.[5] In determining whether or not a body is a "court or tribunal of Member State" the European Courts will take a number of issues into account, namely whether—

1. it is established by law,
2. it is permanent,
3. its jurisdiction is compulsory,
4. it has an inter partes procedure,
5. it applies rules of law, and
6. it is independent.[6]

However, these criteria are not absolute. In Broekmeulen v Huisarts Registratie Commissie[7] the ECJ ruled that a body established under the auspices of the Royal Medical Society for the Promotion of Medicine was a "court or tribunal" within the meaning of the treaty, even though that society was a private association. Also the Benelux Court of Justice was considered a court within this context, as a court common to several (Netherlands, Belgium, Luxembourg) Member States. Also the Unified Patent Court, as a court common to several Member States is expected to be able to ask prejudicial questions.

Article 267 of the Treaty on the Functioning of the European Union (TFEU) establishing the preliminary reference procedure differentiates between the right and the duty of national courts to seek a preliminary ruling. Under the discretionary reference stipulated in Article 267(2) TFEU, a national "court or tribunal" may ask the CJEU to give a preliminary ruling if it considers that a decision on the question is "necessary" to enable it to give a judgment in a particular case. The obligatory reference (duty to refer) is established in two cases: with respect to national courts adjudicating at last instance (Article 267(3) TFEU ) and with respect of all courts faced with a question of the validity of EU law. The obligation of national courts of last instance to refer for a preliminary ruling when a question of the interpretation of EU law arises is subject to certain exceptions. In accordance with the jurisprudence of the Court, a national court is relieved from the duty to refer (i) when EU law questions are not relevant to the decision in the main proceedings, (ii) in a situation before a national court is “materially identical with a question which has already been subject of a preliminary ruling in a similar case” (‘acte éclairé’), or (iii) when the proper interpretation of EU law is “so obvious as to leave no scope for any reasonable doubt” (‘acte clair’).[8]

The Court of Justice Decision has the force of res judicata. It is binding not only on the national court on whose initiative the reference for a preliminary ruling was made but also on all of the national courts of the Member States.

In the context of a reference for a preliminary ruling concerning validity, if the European instrument is declared invalid all of the instruments adopted based on it are also invalid. It then falls to the competent European institutions to adopt a new instrument to rectify the situation.[9]

The European Court of Justice is competent to give rulings regarding the interpretation of treaties to which the European Union is a party, as those treaties are considered to be part of EU law. ECJ is however also competent regarding the application of certain treaties between EU member states, although the procedure may be subject to different procedures. Two such treaties are the 1968 Brussels Convention on jurisdiction in civil and commercial matters and the 1980 Rome convention on applicable law (now mostly replaced by the Brussels I and Rome I regulations respectively).

The possibility to ask for a preliminary ruling is also embedded in other legal systems.

• The courts of Belgium, the Netherlands and Luxembourg may ask "questions regarding the interpretation of the law" to the Benelux Court of Justice regarding certain Benelux conventions and regulations.
• Iceland, Liechtenstein and Norway may request the EFTA Court of Justice for an "advisory opinion" regarding the interpretation of the European Economic Area Agreement, as well as EU regulations that apply to those states.