Resolution criteria: - "Yes": Wins if a person other than Andy Burnham is formally appointed as Prime Minister of the United Kingdom by the monarch strictly after 2026-09-30T17:41:04.813Z UTC and at or before 2027-01-01T00:00:00.000Z UTC. - "No": Wins if no such appointment occurs — that is, Andy Burnham remains Prime Minister of the United Kingdom through 2027-01-01T00:00:00.000Z UTC with no successor formally appointed within the window. Clarifications: - The incumbent Prime Minister at window open is Andy Burnham, who took office on 20 July 2026. A "new" Prime Minister means any individual other than Burnham who is formally appointed to the office by the monarch within the specified window. - Formal appointment occurs when the monarch invites a new individual to form a government at Buckingham Palace, as reported by credible news sources or official UK government announcements.