Wes Streeting, Britain’s health secretary, quit his post on Thursday, citing a loss of confidence in Prime Minister Keir Starmer. His resignation could trigger a Labour Party leadership contest if he secures backing from 81 MPs, the threshold for a challenge.

Streeting’s move follows a string of local election defeats that saw Labour lose ground across England, Scotland and Wales, the worst local result in a century. Starmer, who promised stability in 2024, has faced criticism over policy swings and a controversial ambassador appointment.

If a leadership race erupts, rivals such as Angela Rayner and Andy Burnham may enter, potentially fracturing the party further. Investors watching the UK market will note the political uncertainty could ripple into fiscal policy and investor confidence, prompting a reassessment of the government’s economic agenda.