Prime Minister and Cabinet
Introduction
The Prime Minister and Cabinet are the central institutions of the executive branch of the United Kingdom constitution. The Prime Minister is the head of government, appointed by the monarch as the person most likely to command the confidence of the House of Commons. Cabinet, comprising senior ministers chosen by the Prime Minister, is the formal decision-making body of government. Together, they exercise the great majority of executive authority, including the direction of domestic policy, the conduct of foreign affairs, and the management of the legislative programme. Despite their centrality, the powers of the Prime Minister and Cabinet derive largely from constitutional convention and the royal prerogative, not from any single statutory instrument.
Appointment of the Prime Minister
The Prime Minister is appointed by the monarch through the exercise of the royal prerogative. The convention governing appointment is clear: the monarch must appoint the person who is best able to command the confidence of the House of Commons. In practice, this is the leader of the political party that wins the most seats in a general election. Where no single party commands an overall majority, the monarch’s private secretary conducts discussions with party leaders to identify who can command confidence, as occurred after the 2010 election. The monarch’s role is strictly neutral and non-discretionary in ordinary circumstances. The Prime Minister holds office at the monarch’s pleasure but by convention resigns only after electoral defeat, loss of confidence, or personal decision. The Cabinet Manual (first published in 2011) codifies key conventions, including the process for government formation and the caretaker convention during hung parliaments.
Cabinet Government and Collective Responsibility
Cabinet government is the principle that major policy decisions are taken collectively by the Cabinet rather than by the Prime Minister alone. Cabinet is composed of Secretaries of State heading government departments, together with other ministers invited by the Prime Minister, including the Chancellor of the Exchequer, the Foreign Secretary, and the Lord Chancellor. Cabinet meets weekly while Parliament is sitting under the chairmanship of the Prime Minister. The principle of collective ministerial responsibility requires that Cabinet decisions are binding on all ministers, who must support government policy publicly or resign. Collective responsibility ensures government unity and enables the government to command confidence collectively. Exceptions exist: during the 2016 EU referendum, Cabinet ministers were permitted to campaign on opposite sides, and the Coalition Agreement (2010–2015) provided for agreed disagreement on certain issues. The Ministerial Code sets out the rules governing Cabinet government and ministerial conduct.
Prime Ministerial Powers
The Prime Minister’s powers have grown significantly over the twentieth century, leading some commentators to describe the office as presidential in character. The Prime Minister controls the composition of the Cabinet through appointment, reshuffle, and dismissal powers. The Prime Minister sets the Cabinet agenda, chairs meetings, and makes the final determination of collective decisions. The Prime Minister controls the machinery of government, determining the structure and allocation of departmental responsibilities. The Prime Minister represents the UK internationally and exercises prerogative powers over foreign affairs, treaties, and armed conflict. The Prime Minister advises the monarch on the dissolution of Parliament, the appointment of senior judges, bishops, and peers, and the grant of honours. The Prime Minister’s Office in the Cabinet Office, headed by the Chief of Staff and the Principal Private Secretary, provides support for these functions. Critics argue that the growth of prime ministerial power has diminished Cabinet government and weakened collective accountability.
Cabinet Committees
Much of the detailed work of Cabinet is conducted through Cabinet committees, which consider matters requiring collective decision without requiring the full Cabinet’s involvement. Committees include the National Security Council (dealing with defence, foreign policy, and security), the Economy and Business Committee, the Home Affairs Committee, and the Parliamentary Business and Legislation Committee (the “Legislation Committee”). The Prime Minister determines committee membership and chairs the most important committees. The practice of written ministerial minutes and correspondence allows decisions to be taken without formal meetings. The Cabinet Secretary and the Cabinet Secretariat support the committee system. The use of informal groups and bilaterals (Prime Minister–minister meetings) has increased, raising concerns that formal Cabinet decision-making is being bypassed.
The Cabinet Manual
The Cabinet Manual (first published in 2011, updated in 2014) is a government document that sets out the main laws, conventions, and rules governing the operation of government. It covers the appointment of the Prime Minister, Cabinet government, collective responsibility, the role of the opposition, the civil service, and the relationship between the executive and Parliament. The Manual is not legally binding but provides authoritative guidance on constitutional practice. It draws together previously scattered conventions and procedural rules into a single accessible document. The Ministerial Code is a separate document that sets out the standards of conduct for government ministers, including requirements for the declaration of interests, the handling of government information, and the maintenance of collective responsibility. Breaches of the Code can lead to resignation or dismissal, though enforcement is ultimately a matter for the Prime Minister.
The Fixed-term Parliaments Act and Its Repeal
The relationship between the Prime Minister and Parliament was significantly affected by the Fixed-term Parliaments Act 2011, which removed the Prime Minister’s prerogative power to seek dissolution and established fixed five-year terms. The Act was motivated by coalition politics and concerns about Prime Ministers manipulating election timing. It created difficulties during the 2017–2019 Parliament, when Prime Minister Theresa May was unable to secure the two-thirds majority required for an early election and later when the government was unable to pass its legislative programme. The Act was repealed by the Dissolution and Calling of Parliament Act 2022, which restored the Prime Minister’s discretion to advise dissolution and reinstated the monarch’s power to dissolve Parliament on that advice. The 2022 Act includes a provision that the dissolution power is not justiciable, preventing court challenges to its exercise.
Conclusion
The Prime Minister and Cabinet remain the apex of the UK executive, exercising extensive powers derived from the royal prerogative, statute, and convention. The relationship between the Prime Minister and Cabinet is in constant tension: the Prime Minister’s growing authority strains against the principle of collective decision-making. The resilience of Cabinet government depends on the political context, the personality of the Prime Minister, and the strength of constitutional conventions. The Cabinet Manual and Ministerial Code provide important codifications of practice, but the core of executive power remains governed by unwritten convention. The future trajectory of executive power will depend on the effectiveness of parliamentary scrutiny, the willingness of Cabinets to assert collective authority, and the continuing evolution of constitutional norms in an era of political instability.