The date by which Prime Minister Keir Starmer is expected to announce his resignation has shifted 2 days earlier, from 16 September 2026 to 14 September 2026, according to the latest Polymarket data.
The change in the implied resignation date comes as the probability of Starmer remaining PM on that date has dropped to ~86%, down from earlier forecasts. Polymarket traders are now pricing in an increased likelihood of the Labour leader stepping down in the coming weeks.