Justice of the Supreme Court of the United Kingdom

Justices of the Supreme Court of the United Kingdom are the judges of the Supreme Court of the United Kingdom other than the president and the deputy president of the court. The Supreme Court is the highest court of the United Kingdom for all civil cases, and for criminal cases from the jurisdictions of England and Wales and Northern Ireland. Judges are appointed by the British monarch on the advice of the prime minister, who receives recommendations from a selection commission.

The number of judges is set by section 23(2) of the Constitutional Reform Act 2005, which established the Supreme Court, but may be increased by Order in Council under section 23(3). There are currently twelve positions on the court: the president, the deputy president, and ten justices. Judges of the Court who are not already peers are granted the judicial courtesy title of Lord or Lady.

The Supreme Court of the United Kingdom is required to have judges with experience of, and practice in, the legal systems of England and Wales, Scotland or Northern Ireland. Once appointed to the Supreme Court, each judge acts as a representative for their distinct legal system in which they practice, whether it be English law, Scots law or Northern Ireland law.

Lords of Appeal in Ordinary, colloquially known as law lords, were judges appointed to the House of Lords of the United Kingdom to carry out the House's judicial functions under the Appellate Jurisdiction Act 1876, which included serving as the final court of appeal for most domestic matters.

On 1 October 2009, the Appellate Jurisdiction Act 1876 was repealed by the Constitutional Reform Act 2005, which created the Supreme Court of the United Kingdom. The House of Lords thus lost its judicial functions and the power to create law life peers lapsed, although the validity of extant life peerages created under the Appellate Jurisdiction Act 1876 remains intact. Lords of Appeal in Ordinary who were in office on 1 October 2009 automatically became justices of the Supreme Court of the United Kingdom. At the same time, those Supreme Court justices who already held seats in the House of Lords lost their right to speak and vote there until after retirement as justices of the Supreme Court.

The House of Lords historically had jurisdiction to hear appeals from the lower courts. Theoretically, the appeals were to the King (or Queen) in Parliament, but the House of Commons did not participate in judicial matters. The House of Lords did not necessarily include judges, but it was formerly attended by several judges who gave their opinions when the Lords desired. They did not, however, have the power to vote in the House.

In January 1856, to permit legally qualified members to exercise the House's appellate functions without allowing their heirs to swell the size of the House, Sir James Parke, a judge, was created a life peer as Baron Wensleydale. As the House of Lords eventually decided that a peerage "for the term of his natural life" did not allow him to sit and vote, Parke also received a hereditary peerage on 23 July 1856.

In 1873 William Ewart Gladstone's government passed the Judicature Act 1873, which reorganised the court system and abolished the appellate jurisdiction of the House of Lords in respect of English appeals. In February 1874, before the Act came into force, Gladstone's Liberal Government fell. The Conservative Benjamin Disraeli became prime minister. In 1874 and 1875 Acts were passed delaying the coming into force of the Judicature Act 1873. The Appellate Jurisdiction Act 1876 repealed the provisions rescinding the jurisdiction of the House of Lords. Additionally, the Act provided for the appointment of two persons to be Lords of Appeal in Ordinary, who were to sit in the House of Lords under the dignity of baron. Originally, though they held the rank of baron for life, they served in Parliament only while holding judicial office. In 1889, however, an Act was passed allowing Lords of Appeal to continue to sit and vote in Parliament even after retirement from office.