Andy Burnham's consolidation of Labour's leadership since succeeding Keir Starmer in July 2026 stands as the dominant factor behind traders assigning an 89.5% chance to exactly two prime ministers holding office by the end of 2027. His administration has delivered polling gains that reversed earlier deficits to Reform UK, while recent local setbacks and ministerial exits under the prior leader prompted no immediate repeat instability. The October budget's modest measures and repeated early-election denials have further reduced near-term turnover risks, even amid persistent Westminster speculation about a 2027 vote. With the next general election not required until 2029 and no major policy shocks in the past month, the market reflects broad agreement that Burnham will serve through the period, keeping the odds of three or more leaders very low.