Will Keir Starmer leave Prime Minister of the United Kingdom before Sep 1, 2026

30-day trend

Analysis

Markets are currently pricing a 61% probability that Keir Starmer will leave his position as Prime Minister before September 1, 2026—roughly four months from now. This elevated probability reflects uncertainty about the sustainability of Labour's government following its 2024 election victory. The main drivers include Labour's relatively narrow working majority in Parliament, ongoing economic pressures, and potential internal party dynamics that could force leadership changes or trigger an election. Key catalysts would include significant by-election results, major policy failures, or shifts in Labour party cohesion. The timeframe is relatively short, meaning any departure would likely stem from immediate political crisis rather than normal electoral cycles. Market pricing suggests traders view near-term stability as contested but more likely than not to hold through summer.

• ›Labour's current House of Commons majority and the number of seats required to trigger a government collapse through defections or by-election losses
• ›Economic indicators and public approval metrics in the UK between May and September 2026, as these typically drive confidence votes or election calls
• ›Internal Labour party dynamics and any major policy implementation failures that could destabilize Starmer's position
• ›By-election schedules and results that could shift the parliamentary arithmetic and pressure on government stability
• ›External shocks or crises (economic, security, or political) that could accelerate leadership change timelines

What moved the line

• Jun 22Before Jul 24, 2026↑40pp52→92¢ · Kalshi
• Jun 22Before Jun 23, 2026↑34pp44→78¢ · Kalshi
• Jun 21Before Jun 27, 2026↑32pp53→85¢ · Kalshi
• Jun 19Before Jul 1, 2026↑22pp25→47¢ · Kalshi
• Jun 21Before Jul 1, 2026↑21pp66→87¢ · Kalshi

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These markets stopped trading. Last odds and any captured outcome are shown above — full settlement detail lives at the venue.

How we compute these odds