Before the establishment of the Supreme Court, the House of Lords functioned as the highest court in the UK. However, this system was criticized for a number of reasons, including the confusion between the legislative and judicial roles of the House of Lords. The Judiciary Act of 1701 had initially created the House of Lords as the final court of appeal, but over time, the role became increasingly problematic.

The separation of powers doctrine, fundamental to democratic governance, was challenged by the overlapping functions of the House of Lords, which was composed of both judges and political figures.

The Constitutional Reform Act 2005 sought to address these issues and establish a clearer distinction between the judiciary and the legislature. The Act, which came into effect on October 1, 2009, created the Supreme Court of the United Kingdom as an independent judicial institution. The creation of this court not only redefined the separation of powers but also modernized the UK’s judicial system, making it more accessible and transparent. The Supreme Court took over the judicial functions previously carried out by the House of Lords, including hearing appeals on constitutional and legal issues.

The Act also led to the establishment of a new position: the President of the Supreme Court. The first President was Lord Phillips of Worth Matravers, who served from 2009 to 2012. Lord Phillips played an instrumental role in transitioning the UK judiciary into the new system, which included the transfer of the judicial functions from the House of Lords to the newly established court.
The Supreme Court was designed to be independent, and its members are referred to as Justices. The court consists of 12 Justices, one of whom is the President. The Justices are appointed by the monarch on the advice of the Prime Minister, and the appointments are made from among senior judges in the UK, including those from the Court of Appeal and the High Court.
Functions and Role The Supreme Court serves several important functions within the UK judicial system. It is the final court of appeal in civil and criminal matters, and it has the power to hear cases of the greatest public and constitutional importance. The court’s role is to interpret and clarify the law, often deciding on issues that affect the interpretation of statutes or the application of common law principles. The court is also responsible for resolving disputes between different parts of the UK, including England, Wales, Scotland, and Northern Ireland.
One of the key functions of the Supreme Court is to ensure that the law is applied consistently and fairly across the country. Its decisions are binding on all other courts, and its judgments are often influential in shaping future case law. The court is also empowered to rule on constitutional issues, including challenges to the legality of government actions, and its judgments can have far-reaching implications for the balance of power between the state and the individual.
The Supreme Court’s jurisdiction covers a wide range of cases, including but not limited to, civil disputes, criminal appeals, and matters of constitutional law. It has the authority to hear cases from any of the four nations that make up the United Kingdom, and it often hears cases that involve multiple areas of law, such as human rights, administrative law, and European Union law. Cases Handled by the Supreme Court
Since its establishment, the Supreme Court has heard numerous significant cases that have shaped the legal landscape of the UK. The number of cases it handles each year varies, but it is known to receive thousands of applications for appeals annually. These applications come from all over the UK and involve cases that raise issues of legal or constitutional importance. However, not all applications are accepted for hearing. The court has strict criteria for selecting cases, and only those that involve points of law of the greatest public or constitutional importance are usually granted leave to appeal. The court’s caseload includes appeals in both civil and criminal matters, and it has been involved in some of the most high-profile legal battles in recent years. Some notable cases heard by the Supreme Court include:  
(i) Miller v. Secretary of State for Exiting the European Union (2017): This landmark case determined that the UK government could not trigger Article 50 (the mechanism to leave the European Union) without parliamentary approval. The court ruled that the government must consult Parliament before taking such a significant step.   (ii) Cherry/Miller prorogation case (2019): In this case, the Supreme Court ruled that the prorogation of Parliament by Prime Minister Boris Johnson was unlawful, as it had an extreme effect upon the fundamentals of democracy.   (iii) R (on the application of UNISON) v. Lord Chancellor (2017): The court ruled that the government’s introduction of employment tribunal fees was unlawful because it prevented access to justice.   (iv) The Gina Miller case on prorogation (2019): The Supreme Court ruled that the advice given by the Prime Minister to the Queen to prorogue Parliament was "unlawful, void, and of no effect." These cases demonstrate the court’s crucial role in upholding the rule of law, ensuring that government actions remain in accordance with the Constitution, and protecting individual rights and freedoms. The selection process for cases is rigorous, and the Justices of the Supreme Court use several criteria to determine whether a case should be heard. These criteria include the legal importance of the issues involved, whether the case raises new points of law, and whether the case has broader implications for society. The court's decisions are made by a panel of Justices, with a minimum of five Justices sitting on any given case. In particularly important cases, the number of Justices can increase to up to 11. The court’s judgment is typically delivered in writing, and its reasoning is made available to the public, ensuring transparency and accountability. The Supreme Court’s influence extends far beyond the cases it hears. Its decisions have a profound impact on the development of the law and the protection of rights in the UK. Its judgments are often cited by lower courts and legal practitioners as authoritative interpretations of the law. The court’s rulings can also influence public policy, and its role in shaping legal precedent means that its decisions carry significant weight in the UK legal system. One of the Supreme Court’s most important functions is to ensure that the government acts within the law. In doing so, the court plays a central role in upholding the rule of law and safeguarding democratic principles. Its judgments in cases involving human rights, constitutional law, and the separation of powers have far-reaching consequences for the operation of the UK government and the protection of individual freedoms. The Supreme Court also engages with the public by holding public hearings, making its judgments accessible to the media and the general public. This transparency ensures that the judicial process remains open and accountable, fostering trust in the legal system.