As anticipated, the local government elections in the United Kingdom on May 7, 2026, resulted in a major setback for the Keir Starmer-led Labour Party. The loss has provided an official pretext for discussions about replacing Starmer as party leader and Prime Minister. It is therefore worth taking a moment to reflect on the process of changing party leaders and Prime Ministers at Westminster, a procedure that often carries significant political implications.
A good place to start is to recognise that there is a quiet truth at the heart of the Westminster system, often overlooked in louder democracies: Prime Ministers do not rule; they endure — until they can no longer.
Prime Ministers are not elected in their own right, nor are they insulated by fixed terms or direct mandates. They are elevated by circumstance, sustained by confidence, and, when the moment comes, removed by the same invisible hands that once lifted them. In Westminster, power is both concentrated and conditional. The Prime Minister is the most powerful figure in government — and, in a peculiar way, the most replaceable.
To understand how a prime minister is replaced, one must first understand what a Prime Minister is: not a sovereign figure but a custodian of parliamentary confidence. Strip away that confidence — whether in the House or within the party — and the office begins to dissolve beneath its occupant. This, by the way, is not a flaw in the system; it is its design.
In principle, there are three pathways through which a prime minister may be replaced in a Westminster democracy.
The first is the most visible: the electoral route. A general election produces a new majority and, with it, a new leader. This is the democratic theatre most citizens recognise. It is orderly, periodic, and decisive — but it is also blunt. It does not distinguish between leader and party; it replaces both.
The second route is parliamentary. A government may lose a vote of confidence in the legislature. In such a case, the prime minister must resign or seek a fresh mandate through elections. This route is dramatic but rare, as it requires governing parties to turn against themselves in full public view. It is, if you will, the nuclear option of Westminster politics.
The third —and most revealing— is the internal party route. This is where leadership is forged and undone.
Parties in Westminster systems are not passive associations; they are disciplined coalitions of ambition, ideology, and calculation. When a party concludes that its leader no longer serves its interests — whether because of electoral risk, political misjudgement, or erosion of authority — it can act. Quietly at first, then decisively. It is here, within the party, that Prime Ministers are most often changed.
The process of replacing the PM differs between the parties. If the Conservative Party has, in recent times, acquired a reputation for speed — some would say impatience — in replacing leaders, the Labour Party has cultivated something more nuanced, more deliberative, and, at times, more conflicted.
Labour does not simply remove leaders; it processes them. Its system involves multiple constituencies: Members of Parliament, party members, affiliated unions, and the broader movement. This creates a form of distributed legitimacy. A Labour leader is not merely the choice of MPs; they are, at least in theory, the embodiment of a wider democratic coalition.
This structure and system are admirable yet complex. They mean that leadership in Labour rests on a delicate balance between parliamentary authority and party sentiment. A leader may command one and struggle with the other. When that balance tilts too far in either direction, pressure begins to build. And pressure, in politics, is rarely announced. It accumulates.
Contrary to popular belief, prime ministers are not overthrown suddenly; rather, their downfall is gradual. The initial indicators tend to be subtle: a pause in public support, a gentle shift in language from allies, the appearance of “constructive criticism” where there was once confidence, and a shift in media tone — from active scrutiny to more speculative commentary.
Then come the signals within parliament. They come in the form of Backbench unease, Briefings — always anonymous, always “senior sources”, Questions framed not against opponents but against direction. And finally, the most telling sign of all: the emergence of alternatives.
In Westminster politics, leaders do not fall into a vacuum. They fall when others are ready to rise.
It is against this backdrop that one must consider the present moment within Labour.
Keir Starmer’s rise to party leadership — and eventually to government — was based on a promise of renewal. He vowed to stabilise a battered party, restore its electoral appeal, and offer a disciplined, credible alternative to a fatigued electorate. In many ways, he has fulfilled the first part of that promise.
Labour has regained its sense of purpose; it has evolved into a genuine governing party rather than remaining mired in perpetual opposition. Discipline has replaced chaos; clear messaging has replaced ideological noise. However, success in opposition does not automatically equate to victory in government — each demands its own test of resilience and skill.
Government sharpens expectations. It exposes not only competence, but direction. It requires not merely the avoidance of error, but the articulation of purpose. And it is here —quietly, cautiously— that questions begin to surface. Not loudly. Not yet.
But in the careful language of political insiders, one begins to hear phrases such as:
- “What is the long-term vision?”
- “Where is the distinctive Labour imprint?”
- “Is stability enough?”
These are not attacks; they are probes. And probes, in Westminster politics, are often the beginning of repositioning. Within the parliamentary party, there remains broad support. Starmer is not a leader under immediate threat. But support in Westminster is not static; it is contingent. It is sustained not only by loyalty, but by belief — belief that the leader is not only safe, but successful; not only competent, but compelling.
Among party members and activists, the picture is more nuanced. Labour’s wider base, always more ideologically expressive, continues to wrestle with the balance between pragmatism and principle. This is not unusual. It is, in many ways, the defining tension of Labour’s modern history.
The question is whether that tension remains manageable — or whether it begins to seek expression through leadership discourse.
If Labour were to move against its leader, it would not do so suddenly. It would follow a recognisable sequence.
First, the conversation phase. Private discussions among MPs, union leaders, and party figures. No declarations, only assessments.
Second, the positioning phase. Potential successors become more visible — not challengers, but “voices of the future.” Policy distinctions emerge. Speeches are noted more closely.
Third, the threshold moment. A sufficient number of MPs signal dissatisfaction — formally or informally — triggering the mechanics of a leadership contest.
Fourth, the decision phase. Unlike the Conservatives, Labour’s process would likely extend to its wider membership. The party would not simply choose a leader; it would debate its direction.
And finally, the transition. If the leader steps aside — or is defeated — the change occurs with an emphasis on continuity of government, even as leadership shifts.
There is a deeper lesson for those of us observing beyond partisan passion.
What the Labour case illustrates, perhaps more than any other, is that leadership in Westminster is not secured by victory alone. It must be renewed.
A Prime Minister is not removed because a rule permits it; they are removed because a consensus forms — first quietly, then unmistakably — that the party requires something different: a different tone, a different direction, or simply a different moment.
In that sense, the question is not whether a prime minister can be changed. That is always possible. The question is whether the conditions for change are maturing.
In the end, the office of the Prime Minister in a Westminster system is best understood not as a position of possession, but as a relationship of confidence. Confidence between the leader and MPs, between the leader and the party, and between the leader and the public.
When that relationship holds, leadership appears secure — even inevitable. When it begins to loosen, even slightly, the most powerful office in the land becomes, once again, what it truly is: conditional. In that condition lie both the strength and the subtlety of the system.
Join me @anthonykila, if you can, to continue these conversations.
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How prime ministers are changed in Westminster