Andy Burnham’s July 2026 succession to Keir Starmer has anchored trader expectations that only two prime ministers will serve through the end of 2027. Starmer resigned amid Labour’s poor local election results and internal pressure, allowing Burnham—an uncontested leadership winner with broad party support—to take office and inherit a large Commons majority. The next general election remains scheduled for 2029, and no major economic shocks, by-election losses, or renewed leadership challenges have surfaced in the weeks since the transition. This stability underpins the 86.5% implied probability for two total leaders, while the modest odds on three or more reflect the high bar for an early contest or snap poll before 2028.