The Supreme Court (initialism: UKSC or the acronym: SCOTUK) is the final court of appeal in the United Kingdom for civil cases, and for criminal cases from England, Wales and Northern Ireland. It hears cases of the greatest public or constitutional importance affecting the whole population, including disputes relating to devolution.

The United Kingdom has a doctrine of parliamentary sovereignty, so the Supreme Court is much more limited in its powers of judicial review than the constitutional or supreme courts of some other countries. It cannot overturn any primary legislation made by Parliament. However, it can overturn secondary legislation if, for an example, that legislation is found to be ultra vires to the powers in primary legislation allowing it to be made.

Further, under section 4 of the Human Rights Act 1998, the Supreme Court, like some other courts in the United Kingdom, may make a declaration of incompatibility, indicating that it believes that the legislation subject to the declaration is incompatible with one of the rights in the European Convention on Human Rights. Such a declaration can apply to primary or secondary legislation. The legislation is not overturned by the declaration, and neither Parliament nor the government is required to agree with any such declaration. However, if they do accept a declaration, ministers can exercise powers under section 10 of the Human Rights Act to amend the legislation by statutory instrument to remove the incompatibility or ask Parliament to amend the legislation.

As authorised by the Constitutional Reform Act 2005, Part 3, Section 23(1), the Supreme Court of the United Kingdom was formally established on 1 October 2009 and is a non-ministerial government department of the Government of the United Kingdom.

It assumed the judicial functions of the House of Lords, which had been exercised by the Lords of Appeal in Ordinary (commonly called “Law Lords”), the 12 judges appointed as members of the House of Lords to carry out its judicial business as the Appellate Committee of the House of Lords. Its jurisdiction over devolution matters had previously been exercised by the Judicial Committee of the Privy Council.

The current President of the Supreme Court is Lord Reed.