Britain heads to the polls in a by-election that could decide Starmer’s future as PM

Polling stations opened at 7am local time, with voting due to close at 10pm. Surveys suggest the seat is being seriously contested by Reform UK, which has risen rapidly in British politics in recent months, and that Labour is facing its toughest electoral test since the May local elections. The constituency, vacated after the sitting MP resigned, has been at the centre of internal party debate for weeks.

At the heart of the campaign sits the possible return to Westminster of Greater Manchester mayor Andy Burnham. He was not a candidate this time, but a parliamentary seat is widely seen as a prerequisite for an eventual leadership bid. If the result goes badly for Labour, left-wing MPs are expected to push Burnham forward as a direct alternative to Sir Keir Starmer.

For the Conservatives and Reform UK, the vote has become a referendum on the Starmer government’s legitimacy. Treasury officials note that recent moves in sterling reflect political uncertainty as much as fundamentals; markets will watch the by-election result almost as closely as the Bank of England’s June interest-rate decision.