Prime Minister Keir Starmer has survived a week of intense manoeuvring by Labour MPs seeking to remove him, but the episode has left him badly weakened and set in motion a leadership contest that could last for months.

The pressure followed dismal results for Labour in local and regional elections on May 7, in which the party shed votes to both the populist Reform UK and the Green Party. More than 80 Labour MPs have since urged Mr Starmer to step down, and four junior ministers have resigned.

Wes Streeting, who quit as health secretary earlier in the week, said he would stand to replace Mr Starmer once a contest is triggered. A day later he threw his support behind Andy Burnham, the mayor of Greater Manchester, who is widely seen as a leading contender.

Mr Starmer has insisted he intends to fight on, telling colleagues he was elected with a large majority and would not abandon his programme. A set of new policy proposals he put forward this week was largely overshadowed by the leadership drama.

The instability has rattled financial markets. The pound fell about 1.3 per cent against the US dollar over the week, and the government’s borrowing costs rose on Friday as investors weighed the prospect of prolonged uncertainty in Westminster.

Under Labour’s rules, formally challenging a sitting leader is procedurally difficult, which is one reason the dispute has not produced a swift resolution. Allies and opponents alike now expect a drawn-out struggle rather than an immediate change.

The crisis has unfolded less than two years into a parliament that Labour entered with a commanding majority, and reflects the speed with which the party’s position has deteriorated amid an energy-driven cost-of-living squeeze and the political rise of Reform UK.