We can divide departures of prime ministers into two broad categories. The first type comes after a General Election, when a party (or group of parties) other than that of the outgoing premier becomes able to command the confidence of the House of Commons. The second general category comes between general elections, when a Prime Minister hands over to a successor of their own party. Of the sixteen transitions that have taken place since 1945, eight have come within the first group, and eight within the second. Mid-term handovers are entirely plausible, therefore. They have often involved pressure to depart being exerted upon a premier from within the governing party itself. This type of exit is presently considered a realistic possibility for Boris Johnson.
The main reasons that people within the Conservative parliamentary party might wish to oust Johnson now are that they find recently-revealed aspects of his behaviour intolerable; and that they see him as having become a public embarrassment and electoral liability. A number, harbouring already-existing objections to Johnson, will see present difficulties as creating an appropriate moment to move against him. They might anticipate that factors such as poor election results, the outcome of investigations by the police, Sue Gray, and the Commons Privileges Committee, and perhaps further revelations, could encourage him to leave. Senior ministerial resignations – if they occurred – could add to the pressure.
Efforts by Conservatives to secure the departure of Johnson have moved beyond discreet, internal efforts alone and clearly into the public arena. But so far, Johnson has proved resilient. Even becoming, in April, the first sitting Prime Minister to be subject to a criminal sanction was not enough to break his resolve. Conservative MPs such as David Davis and Steve Baker think he should already be gone, but he remains. If Johnson sustains his determination to stay on, what are the options, constitutionally, for removing him, and what are the possible obstacles to doing so? One route, that has received much public attention, is through the Conservative Party. If at least 15 per cent of Conservative MPs (54 or more at present) want to, they can instigate a no-confidence vote in Johnson as party leader (among Conservative MPs, through secret ballot). Potentially, the mere triggering of this no-confidence vote, or a win for Johnson that was not sufficiently large, might be enough to convince him that he should give up. (Margaret Thatcher, for instance, left office in 1990 without actually having yet lost in the ongoing challenge to her leadership. Theresa May, however, stayed on after winning a confidence vote by 200 votes to 117 in December 2018 – though she decided to give up the following May). But if a vote of no-confidence in his leadership is held but does not pass, should he choose to persist, Johnson is immune to such challenge for another year.
A further means of ousting Johnson is, in theory, available: a vote of no-confidence in him in the House of Commons. MPs of all parties would take part, and it would therefore not require the support of as many Conservative MPs to pass as would a vote internal to the Conservative parliamentary party. However, Conservative MPs willing to vote in a secret ballot against Johnson as party leader would be more reluctant to do so alongside MPs of other parties on the floor of the House, with their votes made public (for similar reasons, the expulsion of Johnson from Parliament, though technically possible, is hard to conceive of in practice).
If Johnson was removed from the Conservative leadership or – less plausibly – lost the confidence of the House of Commons, then his position would be constitutionally untenable. The only person with the legal authority to remove him is the monarch. But I think it is fair to say that such an intervention would not be necessary. As the Cabinet Manual, a description of various aspects of the UK system issued by the government in 2011, puts it: ‘Historically, the Sovereign has made use of reserve powers to dismiss a Prime Minister’. But they were ‘last used in 1834’ and their employment on this occasion was ‘regarded as having undermined the Sovereign.’ Their use would represent a clear violation of what the Manual describes as ‘the convention…that the Sovereign should not be drawn into party politics’. Johnson, it is true, has shown himself willing to bring the monarch close to controversy, with the unlawful attempted prorogation of Parliament of 2019. But it seems reasonable to conclude that even someone as willing to depart from established principles as Johnson would wish to avoid the degree of opprobrium and possible historical notoriety that failure to leave his post voluntarily in such circumstances would incur. On the same basis, I think we can exclude the possibility of Johnson using the power he now possesses – following the abolition of fixed-term parliaments last month when the Dissolution and Calling of Parliament Act 2022 received Royal Assent and came into force – to use the request of a Dissolution from the Queen as political nuclear option.
In this sense the same self-regard that often appears to drive Johnson to flaunt norms could lead him to abide by them. But his conduct has opened up important areas of discussion about the interaction between behaviour and rules in the UK constitution. Politicians such as Johnson can place any system under strain, whether – as in the UK – it involves an ‘unwritten’ or ‘uncodified’ constitution; or – as in the United States – a ‘written’ or ‘codified’ constitution. But the framework within which such actors operate is also important in conditioning and constraining their behaviour. Who holds high office, how they conduct themselves, and how others respond to them is significant. So is the nature of the institutions and the regulations within which these processes take place. If we wish to address potential weaknesses that have become apparent in the system, we need to consider both aspects, and the way they affect each-other.
Andrew Blick is Professor of Politics and Contemporary History and Head of the Department of Political Economy at King’s College London and Senior Adviser to The Constitution Society.
The Constitution Society is committed to the promotion of informed debate and is politically impartial. Any views expressed in this article are the personal views of the author and not those of The Constitution Society.