There have been a large amount of ECJ cases and judgements that have influenced the UK's legal system, economy and society. Underneath are twelve cases of interest.
1. Van Genda en Loos 26/62  ECR 1:
This ruling first established the doctrine of 'direct effect' of European law.
2. Factortame I C-213/89  ECR I-2433
Along with the Factortame II, these confirmed the supremacy of EU law over the relevant areas of competence such as (in these cases) fishing.
3. Van Duyn v Home Office 41/74  ECR 1337
A case concerning the free movement of workers between member states.
4. Carpenter C-60/00  ECR I-6279
This judgement concerned visa rights and business activity.
5. Mandelli 3/67  ECR 25
A case regarding contract negotiations and the provision of trade.
6. Plaumann v Commission 25/62  ECR 199
A judicial review that concerned the ability to suspend customs duties on imports.
7. Codorniu v Council C-309/89  ECR I-1853
A case concerning the establishment of quota systems for production and the ability of member states in this regard.
8. Humblot 112/84  ECR 1367
Concerned the establishment of internal tax measures and established, along with a later ruling (Commission vs Greece (Car Tax) 1990), that EU member states could not fix the price of goods/services for companies outside their state.
9. Procureur du Roi v Dassonville 8/74  ECR 837
Whether certificates were necessary to be able to trade whisky (and thus other goods) throughout the EU.
10. Bosman C-415/93 ECR I-4921
A judgement that allowed football players (workers) to move from one club to another at the end of their contracts without a transfer fee being required.
11. British Telecom C-392/93  ECR I-1631
A case that looked at the procurement procedures of entities operating in the water, energy, transport and telecommunications sectors and whether the state (UK) had properly implemented the directive.
12. ClientEarth C-404/13  2382
A judgement that found the UK to be in breach of Directive 2008/50 on ambient air quality and cleaner air for Europe.