EU laws in areas for which the EU is responsible override any conflicting laws of member countries.
Two important ideas make this system work. These are ‘supremacy’, meaning the higher status of EU laws compared to national laws, and ‘direct effect’, meaning that EU laws can be relied on in court.
Both these constitutional principles were recognised decades ago in leading decisions of the EU court.
The court said that they were necessary to ensure the survival of the EU legal system and to guarantee that EU rules are followed in all member countries.
The supremacy of EU laws
The principle of supremacy, or primacy, describes the relationship between EU law and national law.
It says that EU law should prevail if it conflicts with national law.
This ensures that EU rules are applied uniformly throughout the Union.
If national laws could contradict the EU treaties or laws passed by the EU institutions, there wouldn’t be this single set of rules in all member countries.
The UK has accepted the supremacy of EU law for some time.