The highest court in a jurisdiction must refer and lower courts may refer to Article 267 TFEU. For the rules in the United Kingdom while it was an EU member state, see s 2(1)
European Communities Act 1972 and Part 68 Civil Procedure Rules. 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 ECJ to give a preliminary ruling if it considers that a decision on the question is "necessary" to enable it to judge 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 function of the obligation to refer is "to prevent a body of national case law not in accord with the rules of [EU] law from coming into existence in any member state": Case 107/76
Hoffmann-La Roche v Centrafarm at 5. Both the highest court in a member state and the Benelux court has the obligation to refer: Case C-337/95
Parfums Christian Dior v Evora. 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 when questions of EU law are not relevant to the decision in the main proceedings, if a national court is "materially identical with a question which has already been subject of a preliminary ruling in a similar case" () or if when the proper interpretation of EU law is "so obvious as to leave no scope for any reasonable doubt".().
Courts that may ask questions What constitutes a "court or tribunal" is a matter of EU law and is not to be determined by reference to national law. In determining whether or not a body is a "court or tribunal of Member State", the EU courts take a number of issues into account: whether it is established by law is permanent, has compulsory jurisdiction, has an
inter partes procedure, applies rules of law and is independent. Only a body that "is established by law... is permanent... [whose] jurisdiction is compulsory... [whose] procedure is inter partes... applies rules of law and... is independent" can be a court or tribunal that may refer: Case C-53/03
Syfait v GlaxoSmithKlein at 29. A body with the right to refer under EU law cannot be deprived of it by national law: Cases 146/73 and 166/73
Rheinmühlen. However, those criteria are not absolute. In
Broekmeulen v Huisarts Registratie Commissie, the
CJEU ruled that a body established under the auspices of the Royal Netherlands Society for the Promotion of Medicine was a "court or tribunal" within the meaning of the treaty even though the society was a private association. Also, the
Benelux Court of Justice was considered a court within that context as a court common to several (Netherlands, Belgium and Luxembourg) member states. Also, the
Unified Patent Court, as a court common to several member states is expected to have the ability to ask prejudicial questions. == Grounds ==