After disastrous local government election results for the Labour Party, speculation has been rife about an internal leadership challenge to Prime Minister Keir Starmer. On Thursday 14 May 2026, the Member of Makerfield, Josh Simons, announced he was resigning his Manchester-based seat (formally given effect by an appointment to an ‘office of profit under the Crown’). The Mayor of Greater Manchester, Andy Burnham, then announced that he is seeking the Labour nomination for the Makerfield by-election so that he can return to the House of Commons. Political commentators speculate that this would position Burnham to challenge for the leadership of the Labour Party. But even with an imminent by-election—expected to be in June 2026—this will take some time and this is taking place against fast-moving developments in the Labour leadership. 

A question has arisen about whether Burnham can even run for the Labour leadership, and become Prime Minister, before the by-election and him becoming a MP. The issue should be separated between the requirements of internal party rules and any constitutional convention. On the former, the Labour Party Rule Book provides that ‘[a]ll nominees [for leader and deputy leader] must be Commons members of the [Parliamentary Labour Party]’: at cl II.2.B.iii. This itself could well preclude Burnham from being a nominee for leader if nominations close before the by-election. The latter is more challenging and has divided academic scholars. This piece will address the issue of convention only. Drawing on examples from nations with a Westminster system of government, I argue that historical practice shows that, as a matter of constitutional convention, a person can be appointed as Prime Minister when they are not a MP, as long as they will imminently become one. (I will describe this period as the ‘interim period’ but this should not be equated with holding office on a caretaker basis where conventions impose limits on the exercise of powers.)

United Kingdom

The notion of a Prime Minister being appointed whilst seatless has in fact occurred in the United Kingdom. Following the sudden resignation of Prime Minister Harold Macmillan, who received the Queen from his hospital bed on 18 October 1963, Her Late Majesty appointed Sir Alec Douglas-Home to be Prime Minister (see my earlier piece about Macmillan’s ‘non-constitutional’ advice). His appointment was effective on 19 October 1963. But on that day, Douglas-Home (then the Earl of Home) was a member of the House of Lords. He resigned from that House, became the Conservative candidate for the safe seat of Kinross and West Perthshire, and was elected on 7 November 1963. There was therefore an ‘interim’ period from Douglas-Home’s appointment on 19 October to his election on 7 November—some 19 days—when he was Prime Minister without being a member of Parliament.

Australia

A similar situation occurred in Australia. Prime Minister Harold Holt went missing on 17 December 1967. A caretaker Prime Minister was sworn in two days later on 19 December to allow the Liberal Party to hold a leadership election. On 9 January 1968, the Party elected John Gorton, who was appointed as Prime Minister and sworn in the next day. At the time of his election and appointment, Gorton was a member of the Senate (the upper House). He resigned from the Senate on 1 February to contest the by-election for Holt’s seat in the House of Representatives (the lower House). This was held on 24 February and Gorton was comfortably elected. Just like Douglas-Home, Gorton served as Prime Minister (in a full, not a caretaker, capacity) for a period of time until he took up his place in the lower House of Parliament.

Ceylon

The notion of a Prime Minister holding office for an interim period until they become a member of a House of Parliament is not confined to where an outgoing Prime Minister falls ill or passes away. In Ceylon, Sirimavo Bandaranaike was the leader of the Sri Lanka Freedom Party, which won a majority in the House of Representatives (lower House) but she did not seek election or secure a seat in Parliament. She was sworn in as the first woman in the world to be Prime Minister on 21 July 1960. But there was a prohibition in the Ceylon Constitution from holding office as Prime Minister if she was not a member of either House four months after the appointment. After a member resigned his seat in the Senate (upper House), the Governor-General appointed Bandaranaike on her own nomination on 5 August. There, again, was a short interim period where the Prime Minister was not a member of either House.

Canada

Canada has several examples of where Prime Ministers have held office without being a member of the House of Commons. The first is Mackenzie King. In 1925, he lost his seat in the general election but his Liberal Party, together with the Progressive Party, formed a minority government. King asked a Liberal MP to resign from his safe seat so that he could run in the by-election, which he won. There was an interim period from the 29 October 1925 election and 15 February 1926 by-election—nearly four months—where King remained Prime Minister without being a MP. In 1945, King was again defeated in his own seat but his Liberal Party could govern with a working majority with the support of Independent Liberal MPs. Just like the first occasion, a Liberal MP in a safe seat resigned so that King could run in a by-election. This interim period lasted from the federal election on 11 June and the by-election on 6 August.

The second and third individuals were John Turner and Mark Carney. In both cases, the sitting Prime Minister (funnily enough, Pierre Trudeau and his son Justin Trudeau) decided to resign. Turner and Carney were chosen as leaders, respectively, in an internal party election. Neither were members of the House of Commons, yet they were appointed by the Governor-General as Prime Minister. Rather than run in by-elections, both Turner and Carney advised the Governor-General to dissolve Parliament and hold a general election. For Turner, he won his seat but the Liberal Party lost the election so he served as Prime Minister (albeit mostly in a caretaker capacity) from 30 June until his election on 4 September 1984 without being an MP (he resigned on 17 September 1984 when his successor was sworn in). For Carney, both he and the Liberal Party won the election but there was an interim period from 14 March to 28 April 2025 where he was a seatless Prime Minister.

A decision to seek a general election, rather than pursue a by-election, can be advantageous in some circumstances. (This would not have been readily available when the now-repealed Fixed-term Parliaments Act 2011 was in force, without two-thirds of the Commons or an Act of Parliament.) A general election can dispel doubts about the legitimacy of the new Prime Minister and allow them to seek a mandate for their leadership. It can be used by the new Prime Minister—especially one who replaced an unpopular predecessor—to ride on a wave of early popularity or the ‘honeymoon phase’.

India

On 1 June 1996, H D Deve Gowda was appointed Prime Minister despite being a member of the Legislative Assembly of the State of Karnataka. He then became a member of the Rajya Sabha (upper House) on 23 September 1996 and served his Prime Ministership from that House. Interestingly, his appointment was challenged in the Supreme Court of India. The Court held that it was ‘clear’ that the Indian Constitution allowed a person who not a member of either House of Parliament to be appointed a Minister in the Central Cabinet (which would include a Prime Minister).

There are two interesting aspects to this judgment. First, the Court rejected a submission from the petitioner that ‘the status of the Prime Minister is distinct from that of a Minister and, therefore, it is essential that a person who occupies the high position of a Prime Minister should be an elected representative of the people.’ The Court stated that this submission ‘overlooks the fact that the person who is appointed the Prime Minister is chosen by the elected representatives of the people and can occupy the position only if he enjoys the confidence of the majority of the elected representatives in the Lok Sabha’ (lower House).

Secondly, the Court observed that, even if a Prime Minister is not a member of either House, ‘once he is appointed he becomes answerable to the House and so also his Ministers and the principle of collective responsibility governs the democratic process.’ This, the Court held, does not violate the ‘norms of democracy’ and ‘the requirement of being accountable to the House would ensure the smooth functioning of the democratic process.’

Discussion

Mark Elliott contends that the suggestion that ‘Burnham could, on an interim basis, become Prime Minister before winning a by-election and becoming an MP’ is incorrect. He says that ‘there is today a clear constitutional requirement’ in the form of a convention or well-settled practice for the Prime Minister to be a member of the House of Commons. Respectfully, the above examples (including the recent example of Carney last year) cast doubt on the inflexible convention that Elliott appears to contend.

Elliott principally relies on the Cabinet Manual at [2.7], [2.8] and [3.1]. However, [3.8] notes that ‘there are examples of individuals being appointed as a minister in anticipation of their becoming a Member of one of the Houses and of continuing to hold office for a short period after ceasing to be Members of the House of Commons.’ The accompanying footnote 7 cites the example of Patrick Gordon Walker. In the 1964 general election, Walker lost his seat despite his Labour Party winning the general election. Nonetheless, he was appointed as Foreign Secretary on 16 October 1964. A fellow Labour MP resigned his safe seat (taking up a life peerage) to allow Walker to stand in a by-election. But Walker lost the by-election and then resigned as Foreign Secretary on 22 January 1965. Not only does this show that examples as old as the 1960s can still be relevant in determining the convention today, but it suggests that there is no good constitutional reason for denying ministerial office to those who anticipate becoming a MP.

Indeed, it is common for there to be a short delay between ministerial appointments who then take up peerages. This is for pragmatic reasons. It allows ministers to immediately start doing work without having to wait for their peerage to be created and to be introduced to the House of Lords. Take two recent examples from the last three years. Lord Hermer became Attorney-General on 5 July 2024 although he did not become a member of the House of Lords until 22 July 2024. And Lord Cameron served as Foreign Secretary from 13 November 2023 without being a member of either House until his life peerage commenced on 17 November 2023. So if a brief lag can be tolerated for one Great Office of State, why not for another?

Elliott contends that there is a good constitutional reason for the convention that the Prime Minister must be an MP: namely, ‘that the British constitutional system hinges upon the capacity of the Prime Minister to command the confidence of the House of Commons’. Elliott is there referencing the principle of responsible government. But that principle does not demand that the Prime Minister always be a member of the House of Commons, just that they have the confidence of that House. That principle, of course, requires that all ministers be politically accountable to a House of Parliament, including by submitting themselves to questioning from members. This is not derogated from if there is a short delay from the moment of taking office as a minister to being a member of the House. Simple steps, such as designating a minister to represent the Prime Minister, can ensure that the Commons can continue to hold them accountable whilst the Prime Minister undergoes either a general election or by-election. Different considerations would apply if, like Walker as Foreign Secretary, a Prime Minister loses the election or by-election that was supposed to make them a member of the House. (This piece does not consider whether, like Ceylon or India, a British Prime Minister can be a member of the House of Lords.)

Leading scholarly works point towards this more flexible approach. S A de Smith and Rodney Brazier in their leading text, Constitutional and Administrative Law (8^th ed), suggest that the rise of party rules for party leaders carried a ‘necessary implication that the Prime Minister, when appointed, shall be a member of, or shall be about to occupy his seat in, the House of Commons’ (at 171). David Butler, in Governing Without a Majority, observed that ‘[a]s Sir Alec Douglas-Home showed in 1963, a man can be Prime Minister while waiting to get back to the House of Commons. But the authority of a seatless Leader would undoubtedly be diminished’ (at 97).

Anne Twomey, in The Veiled Sceptre, catalogues a ‘long history in the Canadian Provinces of occasions when the Premier was without a seat in the legislature’ (at 216–217). The most recent occasion that she catalogues occurred in 2011 when Christy Clark won the leadership of the Liberal Party in British Columbia without being a member of the Legislative Assembly (lower House). Clark was sworn in as Premier on 14 March 2011 and then won a by-election caused by the resignation of her predecessor on 30 May 2011. At the next election on 13 May 2013, she lost her seat, but her party won government. She nonetheless remained Premier. The Government Whip resigned to allow Clark to run in a by-election, which she won on 10 July 2013.

I argue that, in the absence of express provisions (such as s 45 of the Scotland Act 1998 for the Scottish First Minister), the historical practice and scholarly works point towards the constitutional convention having a degree of flexibility. It is imperative that the Prime Minister take steps to become a MP but the historical practice does seem to tolerate a person being appointed as Prime Minister before winning a general election or by-election. As I explained in an earlier piece, the primary convention is that the Sovereign must appoint the person who can hold the confidence of the House of Commons. The fact that there could be practical difficulties with holding a non-MP Prime Minister accountable (as alluded to by Butler and the Supreme Court of India) is a matter for the House to consider.

If Burnham wishes to contest for the Labour leadership in the coming weeks, he faces several hurdles. At the time of writing, he had approval from Labour’s National Executive Committee to stand in the Makerfield candidate selection process. Burnham will then need be selected as the Labour candidate and win the by-election in a seat that Reform UK performed strongly in the recent local government elections. And he would likely need to overcome Labour Party Rules limiting leadership contenders to Commons members. But assuming Burnham can cross all these hurdles, constitutional conventions do not stand in the way of him being appointed Prime Minister before he takes up a seat in the Commons so long as a majority of the House has confidence in him to be the principal adviser to the Sovereign.  

Many thanks to the UK Constitutional Law Association editors for their comments on an earlier draft.

Dane Luo is the Farthing Scholar in Administrative Law at Pembroke College and a Stipendiary Lecturer in Law at St John’s College, University of Oxford

(Suggested citation: D. Luo, ‘Andy Burnham and the Constitution – The Conventions on the Appointment of the Prime Minister’, U.K. Const. L. Blog (20th May 2026) (available at https://ukconstitutionallaw.org/))