Six prime ministers in 10 years: Britain's revolving door shows no sign of stopping

British Prime Minister Keir Starmer announced his resignation Monday (local time), as Britain marks the 10th anniversary of Brexit — its withdrawal from the EU — on Tuesday. The country's cycle of short-lived governments shows no sign of breaking. While immigration and tax increases are frequently blamed for the political instability that has followed Brexit, analysts say the root cause is economic hardship that is unlikely to ease anytime soon.

Britain has cycled through six prime ministers in the decade since Brexit, a pace of turnover that underscores the country's chronic political instability. Starmer, who took office in July 2024, served less than two years.

Sluggish economic growth lies at the heart of each short tenure. Former Prime Minister Rishi Sunak, who himself governed for just one year and eight months, wrote in a Sunday Times op-ed Sunday that European leaders, including those in Britain, "are struggling so much because there is almost no economic growth," adding that "political capital is losing its value faster than ever." Experts say the immigration issue — one of the central arguments for Brexit — has also been driven by the same underlying problem: without economic growth to back it up, public resentment toward immigrants settling in Britain has grown.

The concern is that Britain's economic stagnation will persist long enough to keep the cycle of short-lived governments going. Prolonged inflation and a sluggish economy, now compounded by the shock of the Iran war, have left Britain's economic outlook darker than at any point in recent memory.

The IMF has identified Britain as the country likely to suffer the greatest damage among major economies affected by the Iran war. Britain's low energy self-sufficiency leaves it heavily dependent on imported oil and gas, and its energy storage capacity is significantly limited. When global supply chains are disrupted — as they have been by the Iran war — Britain has almost no buffer to absorb the shock, meaning higher prices are passed directly to households and businesses. The IMF had projected Britain's growth rate at 1.3 percent this year, but revised that figure down to a grim 0.8 percent following the outbreak of the war.

British citizens are already anticipating — or feeling — this deterioration. An economic optimism index published by polling firm Ipsos in April hit its lowest level since the survey began in 1978. The index measures public expectations for the economy over the coming year, and 78 percent of respondents said they expected conditions to worsen — the most pessimistic reading on record. A separate survey of businesses found that 70 percent held a negative outlook.

Britain's chronic low growth has kept tax revenues flat even as successive governments, through frequent changes of power, have allowed welfare spending to balloon to burdensome levels. The cycle has become self-reinforcing: former Prime Minister Liz Truss pushed through unfunded tax cuts that triggered a sharp spike in interest rates and forced her from office, and tight public finances have since prevented bold policymaking, driving out one prime minister after another. Former Prime Minister Boris Johnson warned at a business event Monday that welfare spending "is growing exponentially" and that, if left unaddressed, Britain risks returning to the kind of IMF bailout it required in 1976.

Experts broadly agree that Britain has yet to find a path to the kind of economic growth that could break the cycle. Indriati van Hien, a fund manager at global asset manager Janus Henderson Smaller Companies, told CNBC that "while the prime minister may change, the problems facing the UK economy remain the same," adding that the next prime minister "faces the unenviable task of reviving economic growth while walking a fiscal tightrope." She said energy policy and welfare reform must be addressed in order to bring down the premium on British government bond yields, secure funding for growth and ultimately attract capital flows back to Britain.