Conservative MPs will vote tonight on whether or not to retain Boris Johnson as party leader and Prime Minister. Robert Hazell explains that if Johnson loses, he might step aside immediately or act as caretaker until his replacement is elected. But he might instead stay on and seek to call a snap election, which could place the Queen in the constitutionally awkward position of having to refuse.

The political pundits predict that Boris Johnson will win tonight’s confidence vote amongst the Conservative parliamentary party. But what will happen if he loses, either this time or in a second vote at some point in the future? How long might it take for the Conservative Party to elect a new leader, and how will the country be governed in the meantime?

Under current Conservative Party rules, if more than 50% of all Conservative MPs (currently 180 MPs) vote in support of Boris Johnson, he can stay as party leader and Prime Minister and no new vote can be triggered for 12 months. But the rules can easily be changed. Theresa May won a confidence vote with a majority of 83 in December 2018, but was subsequently forced to announce a timetable for her departure under the threat of a rule change and new vote. She had been under pressure to say that she would go, and finally went after a disastrous European Parliament election result for the Tories in May 2019. Boris Johnson may similarly find that he survives the initial confidence vote, but his long-term position is not secure.

If Boris Johnson loses the confidence vote among Conservative MPs, he is not able to stand again in the contest that will follow (this is a lot healthier than the situation in the Labour Party, where a vote of no confidence by its MPs effectively means nothing: Jeremy Corbyn managed to stand for the leadership after he had failed one dismally in 2016).

Any other Conservative MP can stand for the party leadership in the subsequent election. How long it will take for the party to elect a new leader will depend on the number of candidates standing, and whether the vote goes to a second stage ballot of all party members. Party rules prescribe that Conservative MPs vote initially in a series of ballots to select two candidates, who then go forward to a postal ballot of all party members for the final decision. In 2005 it took two months for David Cameron to be elected leader, defeating David Davis in the postal ballot. In 2019 it took six and a half weeks for Boris Johnson to be elected, beating Jeremy Hunt. But when Cameron announced his resignation in June 2016, it took just 17 days for Theresa May to emerge as the new leader, because Andrea Leadsom stood down as the second candidate in the postal ballot.

In 2016 David Cameron remained in office as Prime Minister until Theresa May had been selected as the new leader, when he then tendered his resignation to the Queen. Similarly in 2019 Theresa May remained in office until Boris Johnson had been selected as leader. But neither of them had lost a confidence vote. The presumption must nevertheless be that Boris Johnson will similarly remain as Prime Minister until a new leader has been chosen, whether that takes a couple of weeks or a couple of months. If (which seems unlikely) he chose to resign immediately, an interim Prime Minister would need to be appointed. That would most likely be Deputy Prime Minister Dominic Raab, so long as he is not standing as a candidate, as he did in 2019. It was Raab whom Johnson asked to lead the government when he went into intensive care in April 2020. Another possibility (an ironic one) could be Theresa May, a party elder who has already served as Prime Minister. The interim Prime Minister would need to have the support of the rest of the Cabinet, and formally would be appointed by the Queen (who might take soundings, as happened with the appointment of Macmillan in 1957, and Lord Home in 1963). Although interim, formally they would have all the powers of a more permanent Prime Minister, chairing meetings of the Cabinet, leading on all the government’s day-to-day business, and responding to emergencies such as the war in Ukraine.

The complications of choosing an interim Prime Minister underline the likelihood that Johnson would remain in office during the election of a new leader. Whether he does so, or an interim is appointed, they are likely to be described as a caretaker Prime Minister. But Boris Johnson or an interim Prime Minister would not lead a caretaker government, in the strict sense of the caretaker convention restricting what a government can do. That only applies when the government has lost the confidence of parliament; Johnson may have lost the confidence of Conservative MPs, but the Conservative government would continue to enjoy a large parliamentary majority, and would be able to govern with the authority conferred by that majority.

The only circumstance in which the caretaker convention would apply would be if Johnson decided to call a snap election, as he is now entitled to do under the Dissolution and Calling of Parliament Act, which came into force on the day it was passed in March. The Prime Minister is now entitled to request a dissolution at a time of his choosing. The Act restored the prerogative power of dissolution, but it is a reserve power of the monarch, which can be refused in certain circumstances. Those circumstances were explained in 1950 by King George VI’s Private Secretary, Sir Alan Lascelles, in a letter to The Times under the pseudonym Senex. The Lascelles Principles state that the Sovereign can refuse a request for dissolution if three conditions are met:

1. if the existing Parliament was still ‘vital, viable, and capable of doing its job’,
2. if a general election would be ‘detrimental to the national economy’, and
3. if the Sovereign could ‘rely on finding another prime minister who could govern for a reasonable period with a working majority in the House of Commons’.

Early dissolution can be justified if a parliament is deadlocked, as happened with the Brexit parliament of 2017-19; it is harder to justify as a solution to contested leadership in the governing party. Sir Alan Lascelles’ principles seem prescient and applicable to current circumstances. He went on to become the Queen’s first Private Secretary in the first year of her reign. As a long reigning monarch with a famously long memory, she will no doubt bear them in mind should Johnson’s last throw of the dice be to request an early dissolution. If Johnson wins the confidence vote, it might be difficult for the Queen to refuse such a request; although she might ask why an election was necessary, given the size of the Conservative majority. But if he lost the vote, and still requested a dissolution, she might rely on Lascelles’ third principle to suggest waiting until a new leader had been selected.

About the author

Robert Hazell is Professor of Government and the Constitution at UCL and a former Director of the Constitution Unit.