Why does Britain keep changing prime ministers? The answer lies in history

Why does Britain keep changing prime ministers? The answer lies in history Prime ministers rarely enjoy an easy ride – but occupants of number 10 seem to have been particularly vulnerable over the past decade. Tim Bale compares modern pressures with previous periods of instability at the top of the political pyramid Enoch Powell, in his biography of Victorian politician Joseph Chamberlain, famously declared that “All political lives, unless they are cut off in midstream at a happy juncture, end in failure, because that is the nature of politics and of human affairs.” Chamberlain never made it to the very top of what Benjamin Disraeli memorably called “the greasy pole” – unlike his son Neville, who did. But for the seven men and women to have occupied the post of prime minister between 2016 and 2026, only for their time in office to be “cut off in midstream” at anything but “a happy juncture”, Powell’s characteristically pessimistic take must surely resonate. Quite why the UK has managed to burn through so many prime ministers in the space of a decade is a question well worth exploring. But it’s also worth asking whether that churn is as unprecedented as many assume – and whether it’s something to which we need to become accustomed: the ‘new normal’, as it were. Familiar story Actually, we’ve been here before – several times, in fact. Between the years 1916 and 1940, for example, Britain had no fewer than 10 prime ministers, though admittedly a couple of them served more than once – Stanley Baldwin three times, Ramsay MacDonald twice. In the 13 years between 1951 and 1964, six individuals served as PM. And between 1970 and 1979, the late queen ‘kissed hands’ with new leaders on four separate occasions. Moreover, though recent events have generated all sorts of explanations as to why Downing Street seems to have a pressing need for a revolving door to be installed, the reasons why prime ministers came and went fairly frequently in those earlier periods are actually pretty similar. It’s down to a combination of intraparty and interpersonal bust-ups, policy U-turns and failures – and the hope that a change at the top might stave off electoral defeat. The reasons why prime ministers came and went fairly frequently in earlier periods are actually pretty similar to those today Obviously, there are one or two differences between the recent and distant pasts. First, owing both to medical advances and to the fact that prime ministers tend to be much younger nowadays, none of the recent run had to step down due to ill health. That’s in marked contrast to some of their 20th-century predecessors: declining health curtailed the premierships of Andrew Bonar Law in 1923, Ramsay MacDonald in 1935 and Winston Churchill in 1955. Second, since 1974 no prime minister defeated at a general election has been permitted by their party to stay on as leader in order to try to win back the keys to number 10. Previously, Baldwin, MacDonald, Churchill and Harold Wilson had done so successfully, Ted Heath markedly less so. So much for the contrasts. What about the similarities that suggest what we’ve seen since 2016 isn’t quite as novel as we might imagine? A good place to start might be a century ago. In December 1916, the mercurial Welshman David Lloyd George effectively forced his boss, Herbert Asquith, out of 10 Downing Street by persuading some of his fellow Liberals – as well as Conservative members of the wartime coalition – that the conflict needed a prime minister prepared to secure victory by any means necessary. Shades, surely, of Boris Johnson convincing Tory MPs in 2019 that he – and only he – could “get Brexit done”? Indeed, the parallels between Johnson and Lloyd George don’t end there. A few years later, in October 1922, while mired in scandal, the prime minister who’d swept all before him in the ‘coupon election’ of 1918 was the victim of what he clearly saw as an outrageous coup against him by a majority of Conservative MPs. Ideologically opposed to many of his policies and convinced that sticking with him could lose them their seats, they replaced him with Bonar Law in the wake of a dramatic meeting at the Carlton Club. That was the very institution where, in June 2022, Tory MP Chris Pincher’s drunken antics triggered the scandal that proved the final straw for those colleagues who wanted rid of Johnson. - Read more | The downfall of Lloyd George Our next parallel – this time with Johnson’s predecessor, Theresa May – is provided by Stanley Baldwin just a year later, in December 1923. He inherited a workable majority from the dying Bonar Law but, like May, felt that he needed a fresh mandate and, ideally, a bigger majority in order to allow him to push through a controversial departure from the platform on which the Conservatives had fought the previous election. In May’s case, of course, the issue for which a strong mandate was needed was Brexit – on which her predecessor, David Cameron, had been defeated at the referendum held in June 2016, triggering his resignation. In Baldwin’s case, it was overturning free trade in favour of tariffs and preferential treatment for imports originating in the British empire. Like May’s gamble, Baldwin’s backfired, resulting in the loss of his majority. But unlike May, he was – despite being a far more skilled politician – unable to cobble together an arrangement with another party that would have allowed him to carry on in Number 10. That failure ushered in the country’s first Labour government in January 1924. New rival Ramsay MacDonald’s minority Labour government lasted less than a year before it was defeated in a vote of no confidence, after which Baldwin’s Tories were returned at the October 1924 general election with a landslide majority. But MacDonald’s party performed well enough to ensure that, from then on, the Conservatives’ main rivals would be Labour rather than the Liberals. Sadly for MacDonald, however, his second term as prime minister, which began in 1929, proved disastrous. Labour MPs and ministers – not for the last time – baulked at their PM and chancellor’s plans to cut public spending and benefits in order to assuage the markets, the media and the opposition. This rebellion prompted MacDonald to jump ship and head up the National Government dominated by Baldwin’s Conservatives. In 1937, Neville Chamberlain succeeded Baldwin as PM, then himself resigned in May 1940 having lost the support of hundreds of Tory MPs following Nazi Germany’s invasion of Norway in April that year. His downfall demonstrates the difficulty (indeed, the impossibility) of carrying on once a significant section of a prime minister’s own colleagues turn against them in the wake of a major policy failure. That’s what happened to Theresa May after her repeated inability to secure an EU withdrawal agreement; to Liz Truss following her disastrous ‘mini-budget’ in autumn 2022; and, of course, to their iconic predecessor Margaret Thatcher, who was ditched when her flagship poll tax looked set to cost the Tories the next election. Labour MPs and ministers baulked at their PM and chancellor’s plans to cut public spending and benefits Anthony Eden suffered the same fate in 1956, having been forced by US pressure to end the Anglo-French military operation to snatch back the Suez Canal, after it had been nationalised by Egypt’s president Gamal Abdel Nasser. It is, nevertheless, important to note that, notwithstanding the fact that he had won a comfortable election victory for the Conservatives not long after taking over from Churchill in 1955, Eden (like May, Johnson, Truss and, now, Keir Starmer) had been driving many of his cabinet colleagues to distraction for some time. Indeed, it is no exaggeration to say that many of them were, frankly, glad to see the back of him when illness provided the excuse that allowed him to jump before he was pushed. Rich pickings The same could be said of Eden’s successor, Harold Macmillan. In October 1963, as his political luck seemed to be running out, he suddenly quit after being temporarily hospitalised. Much to the chagrin of some of the younger members of his cabinet, he helped to ensure that he was replaced not by their favourite, Rab Butler, but by the Tory peer Alec Douglas-Home. The parallel in that case is with Rishi Sunak – and not just because Home was in all probability the wealthiest prime minister of the 20th century, just as Sunak was the wealthiest of the 21st. Like many so-called ‘takeover’ prime ministers, both men – having acceded to the role in controversial circumstances and, therefore, needing to keep as many of their MPs onside as possible – felt unable to ditch policies, priorities and cabinet colleagues that were past their sell-by dates. John Major, who managed to signal a sufficiently significant change from Margaret Thatcher to enable him to win the Conservatives their fourth consecutive term in 1992, is perhaps the exception that proves the rule. Sadly for Gordon Brown – like Eden, a number two forced to wait too long before becoming captain of the ship – he didn’t manage to pull off the same trick when he took over from Tony Blair in 2007. It might, however, be a tad unfair to say the same about Jim Callaghan, who succeeded Harold Wilson in 1976 after a Labour leadership contest widely thought to have included the most impressive group of politicians ever to have fought for the premiership. The authority of every one of the prime ministers who occupied Downing Street after 2016 was eroded by ministerial departures resulting from policy disagreements, personal ambition or a combination of both. Callaghan, though, managed to push a swingeing IMF-inspired cuts package through his cabinet without a single resignation before his government was defeated by Margaret Thatcher three years later. The same, incidentally, applies to Thatcher’s much-maligned predecessor as Tory leader, Ted Heath. He felt that he had to perform a series of spectacular U-turns to cope with similarly challenging economic circumstances as prime minister between 1970 and 1974, the year when he was defeated in two general elections (one in February, the other in October) by Harold Wilson. Many of Eden’s cabinet were glad to see the back of him when illness provided the excuse for him to jump before he was pushed Wilson, having achieved his ambition of regaining the majority he unexpectedly lost in 1970, chose to honour a promise he’d made to his family a few years previously by handing over to Callaghan after 18 months. That made him one of only two prime ministers in the past 100 years to have defied Powell’s aphorism, by leaving Downing Street at a time of their own choosing and with at least a modicum of popularity still remaining. The other was Stanley Baldwin, who had handed over to Neville Chamberlain in 1937. Impossible job? In a parliamentary system such as Britain’s, governments are perfectly entitled to swap prime ministers without holding an election. That they have done so five times since 2016 is actually nothing new. In fact, as we have seen, it is by no means uncommon, having happened five times between 1916 and 1940 and six times between 1945 and 2007. The big difference, of course, is the rate at which they have effected such a swap: five times in just 10 years compared with 24 and 62 years, respectively. One commonly heard explanation for this acceleration is that the job of prime minister has simply become more difficult – perhaps even impossible – over time. Clearly there is some truth in that view: the state has assumed more responsibilities over the past 100 or so years, and running it has become more complex than used to be the case. Meanwhile, the increasing demands on the role imposed by the advent of 24-hour news and social media have also made the spotlight on the PM a whole lot harsher. The authority of every one of the PMs who occupied Downing Street after 2016 was eroded by ministerial departures As we have seen, though, even in the early part of the 20th century, the geopolitical, financial and internal party pressures under which prime ministers operated were often intense, as was competition among their colleagues to replace them given half the chance. All of which suggests that the explanation for the accelerating rate of churn may actually lie elsewhere. - Read more | Alleged coups and government traitors: conspiracy theories in 20th-century British politics A far bigger difference between the recent and more distant pasts is the sheer volatility of the modern British electorate. Voters today will swiftly switch their support if their (arguably unrealistic and inflated) expectations aren’t immediately met. And that’s much harder for governments to do now that rapid economic growth seems to be more and more difficult to generate. Is it any wonder, then, that MPs, bombarded as they now are by opinion polls that suggest they’re going to lose their seats unless they make a change, act accordingly – and more often, and more ruthlessly, than ever before? Tim Bale is professor of politics at Queen Mary, University of London This article was first published in the September 2026 issue of HistoryExtra Magazine