This Insight looks at how a new government is formed under a combination of the royal prerogative (non-statutory powers) and statute (Acts of Parliament). 

The appointment of ministers 

A government comprises ministers, the most senior of which form the Cabinet. The Cabinet Manual states that: 

It is for the Prime Minister to advise the Sovereign on the exercise of the Royal Prerogative powers in relation to government, such as the appointment, dismissal and acceptance of resignation of other ministers […] 

According to Lord Young of Old Windsor, a Private Secretary to the late Queen Elizabeth II, the Monarch “informally” approves the appointment of ministers, which is then followed up “in slightly slower time” with a signed submission (a document) for their approval.  

On becoming Prime Minister in July 2016, for example, Theresa May made a formal submission to Queen Elizabeth II recommending the appointment of ministers. This began: 

Mrs May, with her humble duty to The Queen, has the honour to recommend the attached list of ministerial appointments for Your Majesty’s most gracious approval. 

The Queen signified her acceptance of the advice by writing “Approved” along with her initials in the upper right-hand corner of the submission. 

The Cabinet Manual says that while the appointments of junior ministers “generally take effect from when the Sovereign accepts the Prime Minister’s recommendation of the appointment”, more senior appointments must be confirmed by formal documents or seals of office. 

Meeting of the Privy Council 

The next important stage in the formation of a government is a meeting of the Privy Council, which is a body of advisers to the King. In 1979 and in 1997, this meeting took place on the Saturday following polling day. 

Privy Council oaths 

During the meeting, which is arranged by the Privy Council Office, new Cabinet ministers who are not already members of the Privy Council (Privy Counsellors) swear or affirm the statutory Oath of Allegiance, the non-statutory Privy Council Oath and the statutory Oath of Office (also known as the official oath).

Ministers who are not already Privy Counsellors kneel on a stool to take the Privy Council Oath, after which they physically kiss the King’s hand. Both existing and newly sworn Privy Counsellors who are ministers are then required to swear or affirm the Oath of Office, which they do while kneeling. They then stand up and are handed their seals of office by the King.

Under section 5 of the Promissory Oaths Act 1868, the Oath of Allegiance and Oath of Office must be taken by senior ministers listed in the schedule to that act “as soon as may be after his [or her] acceptance of office”. The schedule lists the: 

  • First Lord of the Treasury (the Prime Minister) 
  • Chancellor of the Exchequer 
  • Lord Chancellor 
  • Lord President of the Council 
  • Lord Privy Seal 
  • Chancellor of the Duchy of Lancaster 
  • President of the Board of Trade 
  • Paymaster General 
  • all Secretaries of State 

The Promissory Oaths Order, 1939 provides that the Oath of Allegiance and Oath of Office must be “tendered to and taken” by any “member of the Cabinet” in the presence of “the King in Council” (the Monarch at a meeting of the Privy Council) or, for ministers outside the Cabinet, in the presence of the Lord Chancellor, Lord President or a Secretary of State.  

Seals of office 

Secretaries of State and some other ministers (for example, the Lord Privy Seal) also receive seals of office. The Cabinet Manual says their appointments “take effect by the delivery of those seals by the Sovereign” at the same meeting of the Privy Council.  

Others have their appointments made or confirmed later through Letters Patent (for example, the Attorney General) or Royal Warrant (the Paymaster General). By custom, the Chancellor of the Duchy of Lancaster receives their seals in private audience with the King, usually immediately after the Privy Council meeting at which other ministerial appointments are made.  

Ministers who have not yet received their seals cannot exercise all the functions associated with their office. In 2005, for example, the then Home Secretary Charles Clarke made two written ministerial statements before his appointment was complete. The Prime Minister later stated in response to a written question that the seals formality was “not relevant to the making of statements in the House” 

Uniquely, Queen Elizabeth II died during the formation of Liz Truss’s government in September 2022. Several senior ministers were due to be sworn as Privy Counsellors and receive their seals of office at a virtual Privy Council meeting scheduled for 7 September. This was cancelled and the Queen died the following day. These Cabinet appointments, therefore, were not completed until King Charles III presided at a physical meeting of the Privy Council on 13 September. 

Other considerations 

The Cabinet Manual states that by “convention” someone will only be appointed a minister if they are an MP or a member of the House of Lords. However, there are examples of people “being appointed as a minister in anticipation of their becoming a Member of one of the Houses”. For example, Peter Mandelson was appointed Business Secretary on 3 October 2008 but only created Lord Mandelson 10 days later. 

There are also statutory limitations on the size of a government. Schedule 1 to the Ministerial and other Salaries Act 1975 limits the number of paid ministers (whether sitting in the Commons or Lords) to 109, while section 2 of the House of Commons Disqualification Act 1975 provides that a maximum of 95 ministers, paid or unpaid, may sit in the House of Commons. A Prime Minister can get around the first limitation by appointing unpaid ministers.  

Not all ministers are members of the Cabinet. But the Prime Minister can invite certain non-Cabinet ministers regularly to “attend” Cabinet, such as particular Ministers of State (the rank below Secretary of State). 

Number 10 Downing Street will usually announce new ministerial appointments on Twitter/X and on following the Prime Minister’s submission to the King but before the necessary Privy Council meeting. These will state that the King “has been pleased to approve the following appointments”. A new Cabinet will meet soon after it is appointed and pose for a group photograph inside Number 10 

Further reading 

About the author:Dr David Torrance is a researcher at the House of Commons Library, specialising in monarchy and the constitution. 

Image credit: Number 10, Open Government Licence v3.0, 2017

Corrections and clarifications

This Insight was updated on 15 July 2024 to clarify how new Privy Counsellors take their oaths.