Administrazione Dealla Finanze dello Stato v Simmenthal (case 106/77) [1978] ECR 629
13. The main purpose of the first question is to ascertain what consequences flow from the direct applicability of a provision of Community law in the event of incompatibility with a subsequent legislative provision of a Member State.
14. Direct applicability in such circumstances means that rules of Community law must be fully and uniformly applied in all the Member States from the date of their entry into force and for so long as they continue in force.
15. These provisions are therefore a direct source of rights and duties for all those affected thereby, whether Member States or individuals, who are parties to legal relationships under Community law.
16. This consequence also concerns any national court whose task it is as an organ of a Member State to protect in a case within its jurisdiction, the rights conferred upon individuals by Community law.
17. Furthermore, in accordance with the principle of the precedence of Community law, the relationship between provisions of the Treaty and directly applicable measures of the institutions on the one hand and the national law of the Member States on the other is such that those provisions and measures not only by their entry into force render automatically inapplicable any conflicting provision of current national law but - in so far as they are an integral part of, and take precedence in, the legal order applicable in the territory of each of the Member States - also preclude the valid adoption of new national legislative measures to the extent to which they would be incompatible with Community provisions.
18. Indeed any recognition that national legislative measures which encroach upon the field within which the Community exercises its legislative power or which are otherwise incompatible with the provisions of Community law had any legal effect would amount to a corresponding denial of the effectiveness of obligations undertaken unconditionally and irrevocably by Member States pursuant to the Treaty and would thus imperil the very foundations of the Community.
19. The same conclusion emerges from the structure of Article 177 of the Treaty which provides that any court or tribunal of a Member State is entitled to make a reference to the Court whenever it considers that a preliminary ruling on a question of interpretation or validity relating to Community law is necessary to enable it to give judgment.
20. The effectiveness of that provision would be impaired if the national court were prevented from forthwith applying Community law in accordance with the decision or the case-law of the Court.
21. It follows from the foregoing that every national court must in a case within its jurisdiction, apply Community law in its entirety and protect rights which the latter confers on individuals and must accordingly set aside any provision of national law which may conflict with it, whether prior or subsequent to the Community rule.
22. Accordingly any provision of a national legal system and any legislative, administrative or judicial practice which might impair the effectiveness of Community law by withholding from the national court having jurisdiction to apply such law the power to do everything necessary at the moment of its application to set aside national legislative provisions which might prevent Community rules from having full force and effect are incompatible with those requirements which are the very essence of Community law.
23. This would be the case in the event of a conflict between a provision of Community law and a subsequent national law if the solution of the conflict were to be reserved for an authority with a discretion of its own, other than the court called upon to apply Community law, even if such in impediment to the full effectiveness of Community law were only temporary.
24. The first question should therefore be answered to the effect that a national court which is called upon, within the limits of its jurisdiction, to apply provisions of Community law is under a duty to give full effect to those provisions. if necessary refusing of its own motion to apply any conflicting provision of national legislation, even if adopted subsequently, and it is not necessary for the court to request or await the prior setting aside of such provision by legislative or other constitutional means.
25. The essential point of the second question as whether - assuming it to be accepted that the protection of rights conferred by provisions of Community law can be suspended until any national provisions which might conflict with them have been in fact set aside by the competent national authorities - such setting aside must in every cast have unrestricted retroactive effect so as to prevent the rights in question from being in any way adversely affected.
26. It follows from the answer to the first question that national courts must protect rights conferred by provisions of the Community legal order and that it is not necessary for such courts to request or await the actual setting aside by the national authorities empowered so to act of any national measures which might impede the direct and immediate application of Community rules.
The second question therefore appears to have no purpose.