The Cabinet & Prime Minister

At the centre of British government stand the Prime Minister and the Cabinet — the people and institutions that actually decide what the government does. Yet describing exactly where power lies between them is one of the enduring puzzles of British politics. Is the UK run by a dominant Prime Minister, or by a collective Cabinet, or by something more diffuse? Understanding the core executive — the wider network at the heart of government — is the key to answering that question.

The Prime Minister

The Prime Minister is the head of government. The role rests on no single great statutory office; instead the PM’s authority flows from being the leader of the largest party in the House of Commons and the chair of the Cabinet. From this position the PM draws a formidable set of powers.

Chief among them is patronage: the power to appoint and dismiss ministers, shaping the entire government in the PM’s image and rewarding loyalty. The PM also sets the overall direction and priorities of government, chairs and steers the Cabinet, directs the use of many prerogative powers exercised in the Crown’s name, and serves as the public face of the government at home and on the world stage. Taken together, control of party and Cabinet gives a Prime Minister great influence over the shape of national policy.

But these powers are far from unlimited. A Prime Minister must retain the confidence of the House of Commons and, just as importantly, the support of their own party and Cabinet. PMs depend on ministers and officials to deliver their programme; they face scrutiny from Parliament, the courts and the law; and they are buffeted by events, the media and public opinion. The ultimate limit is stark: a PM who loses the support of their party can be removed, as the recent history of British politics has repeatedly shown. Power, in other words, is held on conditions.

The Cabinet

The Cabinet is the senior committee of government — chaired by the PM and composed of the most important ministers, most of whom head major departments. It is the formal forum where major decisions are taken or ratified and where the work of government is coordinated. Walter Bagehot called the Cabinet the “efficient” part of the constitution: the hinge connecting the executive to the legislature.

Two conventions govern how ministers operate. The first is collective responsibility: once the Cabinet reaches a decision, all members of the government must publicly support it, or resign. A minister may argue forcefully against a policy in private, but in public must defend it — or leave office. This presents a united front and makes the government collectively accountable to Parliament for its policies. The second is individual ministerial responsibility: each minister is personally accountable to Parliament for their own conduct and for the running of their department, with serious failings or misconduct potentially leading to resignation or dismissal.

Much of the Cabinet’s work is done not in the full meeting but in Cabinet committees — subcommittees that examine particular policy areas in detail before decisions are finalised. These allow the enormous workload of government to be managed and shape a great deal of decision-making away from the main Cabinet table.

No.10 and the centre

The operational heart of government is No.10 Downing Street, the office and residence of the Prime Minister. No.10 houses the advisers and staff who support the PM in setting strategy, coordinating policy across departments, managing communications and overseeing the delivery of the government’s programme. Alongside it sit the Cabinet Office, which supports collective decision-making, and the Treasury, which controls public spending and tax. Because the Treasury holds the purse strings, the Chancellor of the Exchequer is among the most powerful figures in any government, and the centre’s grip on finance gives it leverage over every department.

Underpinning all of this is the permanent, politically impartial civil service, which implements policy and advises ministers. Civil servants serve whichever government is in power, providing continuity and expertise that make the decisions of the political leadership work in practice.

The core executive and the power debate

These pieces — the PM, the Cabinet and its committees, No.10, the Cabinet Office, the Treasury and senior officials — together form what scholars call the core executive. The concept is useful because it captures a central truth: power at the top of British government is shared and negotiated, not held by any one person in isolation. Even a dominant PM must work through, and depend upon, this network.

This framing helps make sense of a long-running debate. Some argue that power has increasingly concentrated in the Prime Minister and No.10, producing “prime ministerial” or even “presidential” government in which the PM bypasses Cabinet. Others insist that Prime Ministers remain dependent on Cabinet and party support and can be constrained — or, as several have been, removed. The core executive view reconciles these positions: it suggests that how much power a PM wields is contingent, varying with their party standing, their personal authority, the strength of their colleagues and the pressure of events. The relationship between Prime Minister and Cabinet is not fixed but is constantly renegotiated, which is precisely why the question of who really governs Britain has no single, permanent answer.