In the UK the executive (the Government) is appointed by the leader of the party that wins a General Election, with appointees chosen from MPs and Lords (I think). But is this merely a convention as opposed to a strict rule?

If so, what would be the alternative, and has it ever occurred?

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    The trick here is how you do define the "winner". Just the party with more MPs? Then a coalition of the other parties could get to form a government, if they reach an agreement.
    – SJuan76
    Jan 28, 2019 at 19:49
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    Are there any rules in this area? Is the rule that the winning party or coalition simply "get to form an executive" - by whatever means?
    – 52d6c6af
    Jan 28, 2019 at 19:54
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    As per the 2010 and 2017 elections, the current convention is the incumbent stays as "caretaker" until the political parties have finished having meetings to see if there's a combination that would be able to win votes of confidence and supply (i.e. finance) bills. This is now even written up (in a descriptive, not prescriptive sense) here as paragraph 2.12 etc. assets.publishing.service.gov.uk/government/uploads/system/…
    – origimbo
    Jan 28, 2019 at 20:00
  • Thank you. I suppose the thrust of my question was: are there any rules dictating who (as in which person or persons) gets to decide the executive beyond "the winning party or coalition"?
    – 52d6c6af
    Jan 28, 2019 at 20:18
  • See en.wikipedia.org/wiki/1975_Australian_constitutional_crisis , in which the Govenor-General as representative of the Queen chose who formed a government.
    – pjc50
    Jan 29, 2019 at 15:42

4 Answers 4


This is considered a constitutional convention, in that it's not an official, written-down rule, but it is generally expeted to be followed.

The convention that the government is seen to be accountable to House of Commons started in the 1700s, with the government of Sir Robert Walpole. In 1742, Sir Robert lost what he considered to be a vote of confidence in the government, and so he tendered his resignation to the king.

Since then, the convention has been that HM Government must always have the confidence of the House of Commons in order to govern. When a majority of MPs are from a single party, as is usually the case, such confidence is relatively straightforward for the leader of this party to receive.

When there is a hung parliament, when no party has an overall majority, things get a bit trickier. In this case, the Prime Minister will be whichever leader can get the support of enough parties to get a majority in the Commons. In 2010 and 2017, these both happened to also be the leaders of the largest parties (David Cameron and Theresa May, respectively). However, in 1923, Ramsay MacDonald became Prime Minister despite Labour being 67 seats behind the Conservatives, as the Liberals (with 158 seats) decided to support a Labour rather than a Conservative government.

To summarize: The Prime Minister is the person who can get the support of a majority in the House of Commons, and this is usually, though not necessarily, the leader of the largest party.

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    Given the way Ben rephrased the question in the comments, you might want to pull the fact from behind your link that the Conservative PM Baldwin attempted to continue in power 1923, but had his King's Speech voted down.
    – origimbo
    Jan 28, 2019 at 22:17
  • @origimbo A valid point, though the reason that Baldwin was first to put forward a King's Speech is because he was the incumbent, not because his party was the largest.
    – Joe C
    Jan 28, 2019 at 22:30

Almost everything in British constitutional politics is a convention, rather than a written rule, and this is no exception.

The Queen always invites the leader of the party with the largest number of MPs to form a government first.


By convention the Queen will invite the Leader of the party winning the General Election to try to form a Government, in the event of a hung Parliament she will wait until she is advised who she should invite (typically the Leader of the biggest party).

That person then has complete freedom to appoint whoever they want to fill out the Executive. Traditionally it is drawn from the ranks of the MPs and Peers but this is simply a convention, however there is a practical side in that there needs to be someone to represent the Government in Parliamentary Debates, Departmental Questions etc so the vast majority of the Executive will be drawn from the Lords and Commons.

  • Nitpick with the last sentence: Lords can't enter the Commons, so the need to have a representative there will lead to key roles always being MPs, not Peers.
    – IMSoP
    Jan 29, 2019 at 14:26
  • Yes, I've updated it to make it clear that debates happen in both houses.
    – deep64blue
    Jan 29, 2019 at 14:43
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    @IMSoP Not so the Foreign Secretary has been a Lord in recent times and a Minister of State answers questions in the Commons - last Lord running a department was in 2010 Lord Mandelson = Secretary of State for Business President of the Board of Trade
    – mmmmmm
    Jan 29, 2019 at 16:46
  • When was the last Cabinet member who was not in the Lords or Commons (except the edge cases of resigning as a lord to be able to be elected to the Commons e.g. Douglas-Hume)
    – mmmmmm
    Jan 29, 2019 at 16:49
  • Well the question was about the executive in general not just the Cabinet but off the top of my head Peter Mandelson for a period of 2008 (he was quickly granted a peerage), before that I reckon Patrick Walker and Frank Cousins in 1964 under Harold Wilson.
    – deep64blue
    Jan 29, 2019 at 17:23

It is correct to say this is only a convention and parliament appoints whoever it wishes to be prime minister and form a government. This is typically the leader of the largest party as they command the most votes. If the leader of the largest party can not pass the vote of confidence then other MPs may try. If parliament is unable to pass a vote of confidence to select a prime minister it would have to be dissolved and a general election called.

There is one interesting example (that I could think of) of a prime minister being appointed who was not at the time leader of a party, this was Winston Churchill who was appointed by Parliament after the resignation (from the post of prime minister) of Neville Chamberlain. Churchill formed what was called the wartime coalition, before becoming leader of the Conservative party later that year when Mr Chamberlain resigned from the House of Commons for health reasons.

Perhaps most interestingly Wikipedia suggests

Churchill probably could not have won a majority in any of the political parties

  • On the contrary, it's incorrect to say that Parliament appoints a Prime Minister. Ministers are appointed by the Crown.
    – JdeBP
    Jan 29, 2019 at 6:48
  • @JdeBP this is true but merely a technicality as the crown appoints whoever has a vote of confidence passed in them passed by MPs Jan 29, 2019 at 7:27

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