Power, authority and legitimacy
The nutshell
Power is being able to make things happen. Authority is having the right to use that power. Legitimacy is when most people accept that right as fair.
Every fact on this page comes from official constitution guides and non-partisan explainers. Each source tag — like Parl — opens where a fact comes from.
The basics
What power means
Power is being able to make things happen, or to get others to act. In politics, power is the ability to make decisions that affect a whole country. A government uses power when it makes new laws or sets taxes.
What authority means
Power on its own is just force. Authority is different. Authority is the recognised right to use power, where most people agree that a person or body is allowed to make the decision. In the UK, Parliament holds legal authority. Parliamentary sovereignty means Parliament is the supreme legal authority, and it can make or end any law.Parl
What legitimacy means
Legitimacy is when that authority is widely accepted as fair and rightful. A government is seen as legitimate when people accept that it has the right to govern. In the UK, a government must command the confidence — the support of most elected MPs — of the House of Commons to take and keep office.HoC
Power and authority are not always in one place
The monarch shows how power and authority can sit apart. The King is head of state and gives royal assent, the final step that turns a bill into law.IfG That step is a formality and has not been refused since 1708. The King reigns but does not rule, and acts on the advice of the government.CU So the Crown holds a formal role while the elected government holds the real power.
- Authority that is used within the law is widely accepted as legitimate
- Winning the most seats at an election gives a government a strong claim to govern
- An institution that has lasted a long time can gain acceptance over the years
- A party can win most seats in Parliament without winning most votes
- Some who hold power, such as the House of Lords, are not elected
- When few people vote, the winning party is chosen by only a small share of voters
The deep end6 min
Three ideas that work together
Power, authority and legitimacy are linked but separate. Power is the ability to act. Authority is the recognised right to use that power. Legitimacy is the wider belief that the right is held fairly. Power without authority is force, and authority without legitimacy is hard to keep. In a democracy, legitimacy usually rests on consent — the idea that authority comes from the people.
Where legal authority sits
In the UK, the highest legal authority is Parliament. Parliamentary sovereignty means Parliament is the supreme legal authority and can create or end any law, and the courts generally cannot overrule its legislation.Parl This is the recognised right to make the rules that everyone must follow.
Where the authority to govern comes from
A government's authority to govern is not the same as Parliament's legal authority. By a core convention of the constitution, a government must command the confidence of the House of Commons — the support of a majority of MPs — to take and keep office.HoC That majority normally comes from a general election, which is where the sense of a rightful mandate begins. If a government loses the confidence of the Commons, it can be forced to resign or to call an election.
Where authority and power part: the Crown
The monarch is the clearest example that formal authority and real power are not the same. The King is head of state, appoints the Prime Minister, opens Parliament and gives royal assent to bills.IfG Yet royal assent is a formality that has not been refused since 1708, and the monarch's remaining powers are generally used on the advice of the government. The Constitution Unit at UCL puts it plainly: the King reigns but does not rule, and as head of state is constitutionally obliged to follow the government's advice.CU The authority of the Crown rests on staying politically neutral.