This assignment delves into the world of European Union law and its influence on the courts of the United Kingdom. It begins with an overview of the European Union's legal framework, highlighting key aspects such as the EU Council, Commission, and Court of Justice. The project then moves on to discuss the concept of parliamentary sovereignty, a cornerstone of British constitutional law that has been impacted by EU laws. Through case studies like Lisa Grant vs. South West Trains, it illustrates how European Union decisions have shaped the legal landscape in the UK, often with significant consequences for individual citizens and the broader implications for national laws and regulations.