The five stages of a Labour leadership challenge

Over 90 MPs have already publicly called for Starmer to go, according to analysis by The i Paper. At the same time, four ministers and six parliamentary private secretaries – MP aides to ministers – have resigned.

Amid this turmoil, Health Secretary Wes Streeting is reported to be preparing to launch a formal leadership challenge against Starmer.

And, former deputy prime minister Angela Rayner – whose HMRC investigation concluded on Wednesday with no finding of deliberate wrongdoing – has signalled she is prepared to run if required.

How any of this could translate into an actual change of leader depends on a set of Labour Party rules that, in several important respects, may ultimately favour the Prime Minister.

Stage one: The contest kicks off

A leadership election can begin in one of two ways: Starmer resigns, or a challenger comes forward to force him out.

If Starmer steps down voluntarily, the path ahead is relatively straightforward. Potential successors declare their candidacies and begin building support.

If he refuses to go, challengers must put their name forward and begin actively collecting nominations from Labour MPs.

Unlike the Conservative Party, Labour has no mechanism for a simple vote of no confidence. There is no equivalent of a letter to the chairman of the 1922 Committee.

The process only begins when an individual MP declares they want to stand.

Stage two: Hopefuls must secure backing to get on the ballot

The nominations required depend on whether Starmer is still in post.

If he has not resigned, the bar is lower. Each challenger only needs the backing of 81 Labour MPs – 20 per cent of the Parliamentary Labour Party.

If Starmer has resigned and a vacancy exists, the bar is higher. Candidates must secure the same 81 MP nominations and also win support from either 5 per cent of constituency Labour parties, or from at least three affiliates – at least two of which must be trade union affiliates – comprising 5 per cent of affiliated membership.

Each MP can only back one candidate and cannot split their support across multiple contenders, which limits the number of viable challengers in practice.

Around 90 Labour MPs have publicly called for Starmer to resign, according to reporting by The i Paper. Above the 81 needed to force a contest but no single challenger has yet declared at the time of writing.

Stage three: The contest starts – or it doesn’t

Once nominations close, the field is set.

If one or more candidates have secured sufficient backing, they proceed to a full contest.

They set out their policy platforms, make their case to members and begin campaigning in earnest.

If Starmer has not resigned, he is placed on the ballot automatically – without needing any MP nominations of his own.

This is a fundamental difference from Conservative leadership rules, which require the incumbent to survive a parliamentary confidence vote before a wider contest can proceed.

But the contest might not happen at all. If no individual candidate reaches the required threshold, the process stops entirely – there is no fallback mechanism and no alternative route.

Equally, if Starmer has resigned and only one candidate qualifies, that candidate could become leader without a full membership ballot.

A coronation is possible if the parliamentary party coalesces around a single agreed successor.

Stage four: The NEC and General Secretary set the rules

As soon as a contest is triggered, the National Executive Committee (NEC) begins shaping the process.

The NEC issues procedural guidelines covering nominations, the timetable and codes of conduct for candidates.

The General Secretary of the Labour Party acts as Returning Officer and appoints an Independent Scrutineer to oversee and verify the ballot.

The NEC defines the precise eligibility criteria, giving it significant influence over the composition of the electorate.

In 2016, when MPs attempted to remove Jeremy Corbyn, the NEC ruled that members who had joined in the previous six months could not vote and that constituency parties could not hold meetings during the contest.

That rule still stands, and it could be consequential this time round. The earlier the NEC announces the timetable, the more recent members are locked out of the ballot.

Stage five: Members vote

The contest is decided by a ballot of paid-up Labour members and affiliated trade union supporters.

Since 2015, the party has used a one-person-one-vote system, preventing the same individual from voting both as a party member and as a trade union supporter.

A candidate must win more than 50 per cent of the vote to become leader.

Why the rules could work in Starmer’s favour

The contest uses a preferential ballot: members rank candidates in order of preference.

If no candidate reaches 50 per cent in the first round, the candidate with the fewest votes is eliminated and their votes redistributed to supporters’ second preferences. The process repeats until one candidate crosses the threshold.

Survation polling of 1,078 Labour members conducted for Compass between 30 April and 5 May 2026 illustrates why this matters.

Andy Burnham was the first preference of 42 per cent of members – but his second and third preference tallies were comparatively modest, at 13 per cent and 8 per cent respectively.

Angela Rayner, Ed Miliband and Wes Streeting each took around 10 to 11 per cent of first preferences, with their second-preference scores ranging from 12 to 22 per cent.

In a contest without Burnham – who is not an MP and would need to win a by-election before he could stand – first-preference votes would be far more evenly distributed across the remaining candidates.

As lower-placed contenders are eliminated and their votes redistributed, Starmer’s second-preference support from members who regard him as the safer or most centrist option could prove decisive.

A second Survation poll found that 45 per cent of Labour members thought Starmer should stand down after the local elections, against 42 per cent who believed he should remain.

But 51 per cent did not think he could turn the party’s fortunes around ahead of the next general election – figures that suggest anti-Starmer sentiment is widespread but not overwhelming, and that a significant minority of members may remain open to his continuing in office.