What does the prime minister do?
The Prime Minister is the head of the UK government. They lead the Cabinet, set the government's priorities, appoint and dismiss ministers, and represent the UK abroad. The Prime Minister is usually the leader of the largest party in the House of Commons. They must keep its confidence to stay in office.
The role is not set out in one written law. It has grown through convention over three centuries. The Prime Minister is formally appointed by the King, who invites the person most likely to command a majority in the Commons. They are also First Lord of the Treasury and Minister for the Civil Service, and work from 10 Downing Street. Most Prime Ministers also live and work in Downing Street during their time in office.
Day to day, the Prime Minister chairs Cabinet, decides who runs each department and steers the policy programme in the King's Speech. They answer Prime Minister's Questions in the Commons every Wednesday. They lead on national security, including authorising military action and holding responsibility for the nuclear deterrent. They also meet the King weekly. They also chair key Cabinet committees and set the overall direction of foreign policy.
A Prime Minister can change without a general election if their party picks a new leader. This happened in July 2026, when Labour chose a new leader who then became Prime Minister. Power depends heavily on support from their own MPs. A Prime Minister who loses that support, or loses a vote of confidence in the Commons, usually has to go.
- Sets the government's priorities
- Chooses ministers in reshuffles
- Leads on major crises and security
- Prepares the PM for Prime Minister's Questions
- Coordinates communications and policy
Budget: Funded through the Cabinet Office, a few tens of millions a year. Staff: A few hundred, including civil servants and special advisers
What it runs or funds
Prime Minister's Office, Policy Unit, Delivery Unit, No 10 Press Office, National Security Secretariat
Did you know? 10 Downing Street has over 100 rooms and is connected to No 11 and No 12.
Britain is split. Now you decide.
In Population Decides you take the job yourself, running a full term with a Budget, laws, crises and Prime Minister's Questions.
Play Population Decides freeCommon questions
Who appoints the Prime Minister?
The King, who invites the person most likely to command the confidence of the House of Commons.
Is the Prime Minister elected by the public?
Not directly. Voters elect MPs, and the Prime Minister is usually the leader of the largest party.
How long can a Prime Minister serve?
There is no term limit, as long as they keep their party's and Parliament's support.
What is No 10?
The office of the Prime Minister. No 10 is the office of the Prime Minister.
What other official title does the Prime Minister hold?
First Lord of the Treasury. The PM is also First Lord of the Treasury.