[a] As the United Kingdom's highest appellate court for these matters, it hears cases of the greatest public or constitutional importance affecting the whole population.

The creation of a Supreme Court for the United Kingdom was first proposed in a consultation paper published by the Department of Constitutional Affairs in July 2003.

The paper noted the following concerns: The main argument against a new Supreme Court was that the previous system had worked well and kept costs down.

[13] Reformers expressed concern that this second main example of a mixture of the legislative, judicial and executive might conflict with professed values under the Universal Declaration of Human Rights.

When the state invests judicial authority in those officials or even their day-to-day colleagues, it puts the independence and impartiality of the courts at risk.

[18] The first case heard by the Supreme Court was HM Treasury v Ahmed, which concerned "the separation of powers", according to Phillips, its inaugural President.

At issue was the extent to which Parliament has, by the United Nations Act 1946, delegated to the executive the power to legislate.

One of the most important cases presented to the Supreme Court was the joint cases of R (Miller) v The Prime Minister and Cherry v Advocate General for Scotland, known as Miller/Cherry, on Boris Johnson's unlawful prorogation (suspension) of Parliament, to suppress debate in anticipation of Britain's withdrawal from the European Union, "frustrating or preventing the constitutional role of Parliament in holding the Government to account".

The case carried a large amount of political tension in the context of the process of the United Kingdom leaving the European Union; for some, the ruling "delighted 'Remainers' but appalled 'Leavers'",[20] although some Conservative MPs who sought to withdraw from the EU with an agreement had opposed the prorogation.

[28] More than five justices may sit on a panel where the case is of "high constitutional importance" or "great public importance"; if the case raises "an important point in relation to the European Convention on Human Rights"; if the case involves a conflict of decisions among the House of Lords, Judicial Committee of the Privy Council, or Supreme Court; or if the Court "is being asked to depart, or may decide to depart from" its (or the House of Lords') previous precedent.

[33] In November 2011, The Lord Phillips of Worth Matravers allowed counsel to jointly agree to "dispense with any or all of the traditional elements of court dress" at sittings.

[43] In 2010, Queen Elizabeth II granted justices who are not peers use of the title Lord or Lady, by warrant under the royal sign-manual.

[49] Section 25 of the Constitutional Reform Act 2005 details the requirements for a person to be eligible for appointment to the Court.

[55] The Constitutional Reform Act 2005 makes provision for a new appointment process for Justices of the Supreme Court.

Following a Royal Warrant dated 10 December 2010, all Justices of the Supreme Court of the United Kingdom not holding a peerage are entitled to the judicial courtesy title of Lord or Lady and retain this style for life.

[68] However, there have been calls advocating the discontinuation of this practice since the implementation of the controversial national security law in Hong Kong by China in July 2020.

[69][70] More specifically, members from both Houses of Parliament across the political spectrum have on various occasions either called for the termination of this practice or questioned the appropriateness of it.

[76] She became the first senior British judge to quit Hong Kong's top court after the enactment of the security law.

Amid the controversy, in August 2021, The Lord Reed of Allermuir issued a statement certifying that Hong Kong's judiciary "continues to act largely independently of government".

[77] However, about three months later, the US-China Commission submitted its annual report to US Congress detailing China's situation.

[79] In a statement issued on 30 March 2022, the Foreign Secretary announced that the UK Government could no longer endorse British current judges sitting on the Hong Kong Court of Final Appeal, saying to do otherwise "would risk legitimising oppression".

[81] As of 30 March 2022, six retired British justices continue to sit on Hong Kong's top court.

The Constitutional Reform Act 2005 gave time for a suitable building to be found and fitted out before the Law Lords moved out of the Houses of Parliament, where they had previously used a series of rooms in the Palace of Westminster.

[82] After a lengthy survey of suitable sites, including Somerset House, the Government announced that the new court would be at the Middlesex Guildhall, in Parliament Square, Westminster.

That decision was examined by the Constitutional Affairs Committee,[83] and the grant of planning permission by Westminster City Council for refurbishment works were challenged in a judicial review by the conservation group Save Britain's Heritage.

One features the words "The Supreme Court" and the letter omega in black (in the official badge granted by the College of Arms, the interior of the Latin and Greek letters are gold and white respectively), and displays a simplified version of the crown (also in black) and larger, stylised versions of the floral emblems; this modified version of the badge is featured on the new Supreme Court website,[91] as well as in the forms that will be used by the Supreme Court.