The ECJ established the doctrine of direct effect, holding that EU law creates individual rights that national courts must protect, fundamentally transforming the relationship between EU and national law.

The ECJ established the supremacy of EU law over conflicting national law, holding that member states cannot unilaterally override EU obligations through subsequent domestic legislation.

An Italian lawyer challenged the nationalisation of the electricity industry, arguing Italian law conflicted with the EEC Treaty. The ECJ held that EU law creates a separate legal order that takes precedence over national law. Member States have limited their sovereign rights by creating a body of law binding on both nationals and themselves.

A Dutch national was refused entry to the UK because of her association with the Church of Scientology. The ECJ held that Article 48 EEC and Directive 64/221 could have direct effect, allowing individuals to rely on them in national courts. However, public policy derogations permitted member states to refuse entry based on personal conduct.

German authorities refused to allow French cassis liqueur (15-20% alcohol) to be marketed, requiring 25% minimum alcohol content. The ECJ held this breached free movement of goods. Products lawfully produced and marketed in one Member State must be admitted to other Member States unless justified by mandatory requirements.

Ratti was prosecuted under Italian law for labelling solvents in accordance with an unimplemented EU directive whose deadline had passed. The ECJ held that after the implementation deadline, a Member State cannot apply national law conflicting with the directive and individuals can rely on sufficiently clear directive provisions against the State.

The ECJ established that EU directives can have direct effect against member states, and that personal conduct restrictions on free movement must be based on present threats, not mere membership of organizations.

Helen Marshall was dismissed by Southampton Health Authority at age 62, while men could work until 65. She claimed this breached the Equal Treatment Directive 76/207/EEC. The ECJ held that EU directives can be directly enforced against State bodies (vertical effect) but not private employers (horizontal effect).

Foster was employed by British Gas and sought to rely on EU Directive 76/207 on equal treatment. The CJEU held that unimplemented directives can be enforced against bodies that are under state control, provide public services under state authority, and have special powers beyond normal law.

This landmark case established that UK courts can disapply Acts of Parliament that conflict with EU law and can grant interim relief against the Crown. It fundamentally changed the relationship between EU law and domestic law in the UK.

Two joined cases establishing state liability for breaches of EU law. German beer purity laws prevented French beer imports; UK fishing legislation breached EU law. ECJ held Member States liable in damages where breach is sufficiently serious and causes direct loss to individuals.

House of Lords case on judicial review and human rights before the Human Rights Act 1998. Established limits on courts' ability to review executive decisions based on human rights grounds.

Austrian authorities allowed environmental protestors to block the Brenner motorway for 30 hours, disrupting trade. The ECJ held that the blocking of a major transit route could be justified where it balanced free movement of goods against fundamental rights to freedom of expression and assembly, provided the restriction was proportionate.

ECJ cases developing the Francovich state liability doctrine, establishing that member states are liable for legislative and administrative breaches of EU law where the breach is sufficiently serious and manifestly disregards EU law limits.