Why is the UK losing so many Prime Ministers?

Ben Worthy relfects on the high turnover of UK Prime Ministers since Brexit. He argues that this is caused by a combination of a faioure of leadership, fraying relations with backbench MPs and political fragmentation. 

If Keir Starmer leaves Downing Street soon, the average time in office of a UK prime minster since Brexit will be just 2 years. To put this in perspective, the Italian Prime Minister Georgia Meloni, in a system that is supposedly a merry-go-round for leaders, would meet her fourth UK Prime Minister. Sadiq Khan would be on his seventh.

Why has turnover become so rapid? May, Johnson, Truss and Sunak were all ‘takeover PMs’ who, by definition, inherited deep crises, unhappy parties and whole battalions of difficult problems. But Starmer stands out. He was an election winner, in fact a landslide leader, coming to office via a huge majority in 2024. The last two PMs to win by similar margins did a decade in power.

A number of writers such as Sam Freedman and Anthony Seldon have rightly looked to the problems around the office itself, and whether recent leaders could really do it. To quote the words from my A-level politics exam, ‘the office of Prime Minister is what its holder chooses and is able to make of it’. It is true we seem to have had a succession of leaders who have been unwilling or unable to make much of it except a mess. Barbara Kellerman famously argued that bad leadership can be about incompetence or immorality: May and Truss gave us spectacular policy failures, whereas Johnson’s morals found him out.

I’m not convinced, though, that Britain is ungovernable, any more than it was in the 1970s or 1930s. While poor leadership is part of it, I’d argue it’s a broader problem around three Fs: (perceived) failure, fraying relations and fragmentation. The explanation lies in a tangled spiral of leadership failure, voter fragmentation and, above all what I tell my students is one of the big secrets of British politics, the fraying relationship between governments and their own backbench MPs. Sam Freedman argues PMs are more powerful but more vulnerable. This is because the pillars of prime ministerial stability and longevity are washing away.

Part of the story is indeed one of leadership failure, or at least perceived failure. Starmer took over in the midst of deep ongoing crisis, or crises, in British Politics. As Colm Murphy pointed out, a ‘combination of a difficult inheritance, [and] nasty external shocks’ greeted Labour in July 2024.

What made this worse is that Starmer’s majority, and election promises, gave a sense that these things could be solved. He spoke of  a ‘relentless focus on delivery’. The public had very high expectations and are now quite severely disappointed. His inability to deliver, and his indecisiveness, are now very clear in the public mind. According to Full Fact, Keir Starmer is either the least popular PM since records began, or joint lowest with Liz Truss.

Starmer’s failure then flows into the second factor, that of fraying relations with Labour MPs. This is partly a long term problem. Since the 1970s, MPs of both parties have become more rebellious and less loyal: the rejected, the ejected, and the dejected have a greater influence. Scholars suggest this could be about generational attitudes of MPs or the ending of the rule that lost votes trigger a general election.

Whatever the reason, we can read recent Britain politics through backbench unhappiness: from the ‘mother of all rebellions’ over Iraq in 2003, to the disquiet in 2011 that persuaded Cameron to promise a referendum, and the undoing of Johnson’s Covid 19 policy. There should be a post-it-note somewhere on Starmer’s desk reminding him that of his four immediate predecessors, only one lost an election and three of them were effectively removed by their own MPs.

But this is a Labour issue too. Labour MPs came to office expecting delivery and radical change. The intake of 2024 were new, inexperienced and vitally, as Phil Cowley pointed out, lacking the loyalty to a leader: Starmer, unlike Tony Blair, didn’t have any ‘election winning magic’ and  ‘quite a lot of Labour MPs, think they’re mostly there because of Rishi Sunak rather than because of Keir Starmer’. There’s been a downward spiral since. Not only has Starmer failed to deliver what is needed to win Labour the next election, but MPs have been hit by policies and controversies almost purposely designed to cut across their principles, from Winter Fuel to PIP changes. Policy U-turns have been worsened by the unending Mandelson scandal, which went to the heart of questions about Starmer’s judgement.

There’s then the final part of the jigsaw: fragmentation. Rob Ford and others have long seen the deep fragmentation happening across British politics, meaning elections are no longer a two horse race. This has been a long term phenomenon since the 1990s as greater choice and loss of faith eroded Labour and Conservative support, and the voting system no longer worked in their favour. Britain ‘has now entered an unprecedented era of multi-party politics’ as voters now choose between four rather than two parties. This means, for MPs, that their seats are more vulnerable and marginal. In 2024, one in every five seats (115 overall) in the UK was marginal, more than double the 48 marginals in 2019. Wes Streeting, just to pluck an example, has a majority of 528.

There is now a vicious cycle. Leaders failing to deliver, unhappy MPs rebelling, and seats becoming increasingly vulnerable. This is then worsened by the media focus on disloyalty and unhappiness. The paradox of power is that PMs need time to get things done, as those towards the top of the league tables of PMs show. Yet the dynamics are tending dangerously downwards, towards brief stints before removal and replacement.

This then begs several questions for whoever comes next. Can the next Prime Minister break the negative spiral? Can they deliver enough policy, or at least be seen to deliver it, in the time left? Can they inspire the loyalty of their MPs, over the long term? Can they reverse, or at least slow, the fragmentation of British politics?

By Ben Worthy, author of Ending in failure? The performance of ‘takeover’ prime ministers 1916–2016. The Political Quarterly, 87(4), 509-517 and an updated (2024) From May to Sunak: The Failure of the Brexit Takeovers 2016-2024.