If Prime Minister Keir Starmer Falls, Who Will Replace Him?

After Labour’s heavy local election losses, the question of Prime Minister Keir Starmer’s future has moved from gossip into open crisis with growing disquiet.^[1] Despite various MPs remaining hesitantly supportive of Starmer, Wes Streeting has resigned as Health Secretary and called for Starmer to go. Meanwhile, Andy Burnham is trying to return to Parliament through the Makerfield by-election, likely months away.^[2][3]
The seat has long been Labour territory, but it is not risk-free. Reform UK is expected to treat the contest seriously, while a Green candidate could split the vote on the left, reducing the chances of a Labour victory.^[3] This could lead to an utterly embarrassing gain for Reform.

The timing matters. Burnham cannot stand for Labour leader unless he is an MP. If Starmer falls before Burnham wins a seat, the contest probably favours those already in Westminster. So far, Streeting has held back from initiating the process, though his early resignation is a clear sign of intent (Before triggering a leadership challenge Streeting will ensure he has sufficient support). Additionally, four junior members of the government have resigned alongside Streeting, adding to the pressure on Starmer to resign.

If Burnham wins in Makerfield, the entire race changes. The party would then have a candidate who can present himself as Labour loyalist, with strong support both within the party and among the public, yet differentiated from Starmer’s inner circle.

The sequence of events leading up to a leadership challenge:

1. Starmer comes under pressure after the local elections. Already happened.
2. Government (senior) minsters' resignations increase that pressure. Already happened.
3. Burnham tries to enter Parliament. In process.
4. Labour MPs decide when and whether to force a contest or wait. Yet to be decided, very different contests could result.
5. A formal leadership challenge is triggered, either by Starmer resigning or by a challenger receiving nominations from 20% of Labour MPs. According to Labour’s current parliamentary party, this is reported as 81 MPs. This is the same number of candidates required to go through to the final round.
6. Labour members then vote on the candidates who have made it through that parliamentary stage. In practice, MPs decide who reaches the ballot, but Labour Party members decide the winner.

If there is a leadership election while Labour is still in government, the winner would not automatically become Prime Minister in a legal sense. The monarch appoints the person most likely to command the confidence of the House of Commons. In practice, however, if Labour still has a Commons majority, the new Labour leader would almost certainly become Prime Minister. This has become a familiar process for those observing the British political system.
A leadership challenge at some point looks reasonably probable. The question is when, and who will stand. Here are the known likely contenders, including a rough estimate of their place on the left-right spectrum of the Labour Party.
Andy Burnham

Left-right score: 4/10
Main question: Can he get back into Parliament in time?

Burnham is probably the strongest candidate if he becomes an MP before the contest begins. He has ministerial experience, executive experience as Mayor of Greater Manchester (the UK’s third largest city), and enough distance from the current government to present himself as a reset.

Polling supports this. A recent Survation poll of Labour members found Burnham was the preferred leadership choice of 42% of members, far ahead of Wes Streeting and Angela Rayner, who were both on 11%.^[4] YouGov also found Burnham to be the most popular Labour figure among the public, with 34% viewing him favourably and a net favourability score of +4. He is also the only senior Labour figure polled who is viewed positively by a majority of 2024 Labour voters.^[5]

He served as a minister under Tony Blair and Gordon Brown, then later served as Shadow Home Secretary under Jeremy Corbyn before leaving Westminster.^[6] That does not mean politics is simply repeating old Labour battles. Instead, it shows that Burnham knows government, knows the party, and has spent enough time outside Westminster to avoid looking like another Starmer-era minister. He is therefore seen by many as a potential bridge-builder, capable of bringing some unity to a currently divided party.

A likely Burnham vision is clear: Labour has become too managerial, too cautious and too detached from the people it claims to represent. He can offer a break without sounding like a return to the Corbyn years.

The risk is also simple. He has to win Makerfield first. If the contest begins before he returns to Parliament, he may miss his moment. Makerfield is also not risk-free, with Reform likely to treat the by-election as a major target.^[3]

Overall: Favourite if he gets back into Parliament in time. Given his support among Labour members and across sections of the Parliamentary Labour Party, there is a real chance that enough MPs will wait until he has returned before forcing the issue.

Wes Streeting

Left-right score: 9/10
Main question: Is he the real change that is desired or a sharper version of the same politics?

Streeting is now central to the crisis because he has resigned from government and called for Starmer to go.^[2] That gives him a claim to have acted decisively rather than waiting for the collapse.

Unlike Burnham, Streeting was too young to serve under Blair or Brown. He entered Parliament in 2015, during the Corbyn period, but his real rise came under Starmer. He became one of the most recognizable figures in the Starmer project and later the Health Secretary.^[7]

This background gives him both strength and weakness. His strength is that he is articulate, ambitious and politically sharp. His weakness is that his career is closely tied to the very project now in crisis. Arguably, Streeting is to the right of Starmer, particularly in tone and instinct. His critics also point to his closeness to Peter Mandelson, which reinforces the impression that he represents a harder-edged version of Labour’s right.

Polling shows the difficulty. Survation polling reported by LabourList suggested Starmer would beat Streeting in a head-to-head contest among Labour members, with Starmer on 53% and Streeting on 23%.^[8] Streeting may be respected as a political operator, but that does not mean he is loved by the membership.

Streeting’s case would be that Labour does not need to abandon the centre, but to govern with more clarity, urgency and confidence. His critics would say that this is not a reset, but an even greater lurch to the right, with the intention of merging what remains of the Tory Party with the centre of the Labour Party. This would effectively mean giving up on supporters who have moved to the Greens.

Overall: Serious contender and a very good speaker, but probably not a favourite unless MPs choose discipline over a new trajectory. His clearest path is if Burnham does not stand, or if the PLP (the Parliamentary Labour Party) decides that control matters more than popularity with members.

Angela Rayner

Left-right score: 4/10
Main question: Can she unite the party without looking like compromise for its own sake?

Rayner is the strongest candidate already in Parliament if Burnham cannot stand. She has roots in the trade union movement, a strong personal story, and enough senior experience to look credible.

She entered Parliament in 2015, rose under Corbyn, and then served in senior roles under Starmer. That makes her difficult to dismiss. She has survived different versions of Labour and remained relevant.

Her appeal is that she can offer change without making Labour look reckless. Her weakness is that she may be broadly acceptable without being the overwhelming first choice of enough of the party. In the Survation members’ poll, she was level with Streeting on 11%, well behind Burnham.^[4] In YouGov’s public favourability polling, 22% of Britons viewed her favourably, placing her below Burnham but broadly in the same range as other senior Labour figures.^[5]

Rayner was also damaged by the controversy around her tax affairs. She resigned from government during that scandal, but has now said she has been cleared by HMRC (the tax authorities) of deliberate wrongdoing or carelessness.^[9]That does not erase the political damage entirely, but it does remove one of the most serious obstacles to a leadership bid.

Overall: Most likely winner if Burnham cannot stand. She can appeal to the soft left, parts of the trade union movement, and MPs who want change without a complete rupture.

Al Carns

Left-right score: 6.5/10, though less clearly defined/known
Main question: Is he too inexperienced, or is this his strength?

Al Carns is the wildcard. He was elected as Labour MP for Birmingham Selly Oak in 2024 and is a former Royal Marines officer with a decorated military career. He became Minister for Veterans and People in 2024 and was appointed Minister for the Armed Forces in 2025.^[10]

Carns’s appeal is obvious. He does not look like the usual Labour leadership candidate. At a time when many voters associate politics with managerial language and controlled evasions, Carns offers something more direct: service, discipline, defence, country and action.

That could matter more than people expect. Reform’s rise has created a problem for Labour that is not only economic, but cultural. A candidate with a military background, a state-school story and a strong national-security profile may appeal to MPs who think Labour needs to sound more patriotic and less technocratic.

There are signs that this is being noticed. Carns has recently been discussed as an outsider candidate, and the Guardian listed him among possible contenders if a contest emerges.^[11] The Times also reported that Carns had set out what looked like a mission statement after the local election defeats.^[12]

But the weakness is just as obvious. Carns is very new to Parliament. He has not built the same party network as Rayner, Streeting, Cooper, Miliband or Burnham. He may be admired without being seen as ready to lead the government.

Overall: A real unknown. He is unlikely to win this time, but he could shape the contest. A strong showing would make him a serious figure in the future.

Ed Miliband

Left-right score: 4/10
Main question: Does experience help him, or entrench him in the past?

Miliband has substance, experience and a serious policy profile. He served under Gordon Brown, led Labour from 2010 to 2015, resigned after losing to David Cameron, and later returned to senior politics under Starmer.

His strength is that he can speak with greater depth about climate, inequality, and public purpose than most candidates. His weakness is that he has already led the party and lost before Jeremy Corbyn became leader.

His politics is close to Burnham’s in some respects. Both can be seen as soft-left bridge-builders, generally acceptable to several wings of the party. Miliband also performs reasonably well with the public compared with many other Labour figures. YouGov found 23% of Britons viewed him favourably, the same figure as Starmer and just above Rayner.^[5]

But Miliband’s problem is not only popularity. It is whether Labour wants to reopen a chapter it has already closed. He may be liked, but that does not mean the party wants him back as leader.

Overall: Plausible in a fragmented contest, but unlikely to stand if Burnham enters the race. If Burnham is available, Miliband’s lane becomes much narrower.

Rachel Reeves

Left-right score: 7.5/10
Main question: Can she separate herself from the cautionary economic approach of the Starmer government?

Reeves, the current chancellor (having worked in retail banking and for the Bank of England), would be the candidate of fiscal credibility and institutional reassurance. In another moment, that might be enough. While she does not poll well among the general public, she is generally associated with reassuring business, the Treasury and financial markets.

This matters because the leadership crisis has already destabilised markets. Reuters reported that political turmoil around Burnham’s possible return led to rising UK borrowing costs, a fall in sterling and pressure on bank stocks.^[13] The Guardian also reported warnings from investors about the risk of another “Liz Truss moment” if a leadership contest ignores public finances and market confidence.^[14]

Nevertheless, if Starmer falls, it will probably be because Labour decides that caution itself has become politically damaging. Reeves may be respected, but she would struggle to look like change. She is too closely associated with the economic strategy of the Starmer government.

Overall: Credible, but poorly placed for this specific crisis. Her more likely role may be staying on as Chancellor, signalling continuity to shaken bond/gilt markets under a new leader.

Shabana Mahmood

Left-right score: 8/10
Main question: Is competence enough, or are too many bridges burnt?

Mahmood, the current home secretary, would appeal to MPs who want seriousness, order and control. She could become attractive if the contest becomes chaotic despite sharing the low-energy charisma that hallmarks Starmer's premiership.

Nonetheless, she does not obviously answer the larger political question: how does Labour reconnect with voters who feel ignored or disappointed? Her rhetoric as Home Secretary has alienated parts of the left and liberal centre. She has warned that illegal migration is “tearing our country apart” and has pursued some of the toughest asylum and immigration proposals of the Labour government, including plans to make refugee status temporary, review it every 30 months, and tighten rules around family reunion.^[15]

This is not simply a question of policy. It is also a question of tone. Mahmood has been accused by critics of adopting language too close to that of Reform UK. At a live political event, she told “white liberal” hecklers to “f**k right off” after they accused her of “out-Reforming Reform”.^[16]One of the hecklers later dismissed Mahmood’s description as “laughable”, saying he was himself a migrant and person of colour.^[17]

Her supporters would argue that she is confronting legitimate public concern about immigration. Her critics would argue that she has moved into rhetoric that sounds punitive, divisive and, at times, xenophobic.

That is the Mahmood problem. She may look serious to parts of the PLP, but she has likely lost too much trust on the left of the party and the general public alike. Her route depends on a small field and a desire for order over renewal.

Overall: Competent and serious, but unlikely to gather enough support unless the pool of candidates remains small.

Yvette Cooper

Left-right score: 6/10
Main question: Stabiliser or renewal candidate?

Cooper has long experience and authority. She served as a minister under Tony Blair, entered Cabinet under Gordon Brown, later served in Ed Miliband’s shadow cabinet, chaired the Home Affairs Select Committee, and returned to senior office under Starmer.^[18] She would look safe in a crisis.

Her political positions have also shifted over time, or at least adapted to different moments. She has moved from New Labour ministerial politics, through a more civil-liberties and parliamentary-scrutiny role during the Brexit years, and then back into the harder world of Home Office and foreign policy politics. That breadth is useful, but it also makes her harder to define. She is experienced, but not obviously symbolic of renewal.

Her marriage to Ed Balls is not relevant as a qualification, but it is politically relevant as part of the media and Labour ecosystem around her. Balls is a former Labour shadow chancellor and now a major broadcaster. In 2026, he stopped interviewing Cooper on Good Morning Britain after earlier criticism over impartiality when he interviewed his wife while she was Home Secretary.^[19] If Cooper stood for leader, this would not define her, but it would form part of the wider scrutiny around her public image and political network.

The problem is that a party removing its Prime Minister may not only want safety. It may want someone who symbolises a clearer break. Cooper is serious, experienced and credible, but she may feel more like a stabiliser than an answer.

Overall: Serious, but unlikely unless the party panics and decides that experience matters more than renewal. Seen very much as an establishment figure within the party, she would represent little in the way of forward momentum.

What the Polls Say

The polling picture is clearest around Andy Burnham. A recent Survation poll of Labour members found Burnham was the first-choice successor for 42% of members, far ahead of Wes Streeting and Angela Rayner, who were both on 11%.^[4] YouGov polling points in the same direction among the wider public, finding Burnham to be the most popular senior Labour figure, with 34% viewing him favourably and 30% unfavourably, giving him a rare positive net score of +4.^[20]

The same polling suggests Streeting has a serious membership problem. Survation polling reported by LabourList found that Starmer would beat Streeting in a head-to-head contest among Labour members, while Burnham would beat Starmer heavily.^[21] Rayner appears to be the strongest fallback if Burnham cannot stand, while Miliband remains plausible but burdened by having led before. Cooper, Mahmood, Reeves and Carns currently look like harder routes unless the contest becomes unusually fragmented.

Current Prediction

Assuming the contest takes place: Burnham wins if he gets into Parliament in time. Rayner wins if he does not and by a much tighter margin.
Before considering the successes of the likely candidates, it is worth noting, albeit briefly, how the policy positions of a likely candidate could stifle any leadership challenge. In the 2024 Labour manifesto, strict lines were drawn on what a Labour government would do, including around taxation and remaining outside of the EU single market or customs union.
If any candidate's position is suggestive of a distinct change of path from the manifesto, this may prompt a call for an early general election. Wes Streeting, calling for the UK to rejoin the EU, for example, may worry MPs that an election will be called early, risking their seats. With Labour's massive majority in the Commons, there are many seats to lose. As it stands a general election is likely in 2028/2029.
Hence, MPs may be supportive of particular candidates, assuming a leadership challenge is initiated, but may not themselves begin the process.

Thus, what is the likely outcome assuming a leadership contest is called?

It is also worth mentioning that Kier Starmer is entitled to stand in the contest. Polling suggests he would win against the likes of Streeting, but lose against Burnham. He would, nevertheless, require the 81 MP support like all other candidates.

Burnham has the clearest story. He can argue that Labour needs to reconnect with the country rather than simply replace one Westminster figure with another. Rayner has the clearest internal route if Burnham is not available, and her recent clearance by the tax authorities (finding she had not deliberately or carelessly broken tax rules) removes a major obstacle to any leadership bid.[9] Streeting is dangerous, but likely remains too closely associated with the project Labour would be trying to move beyond.

Carns is the most interesting outsider. Though unlikely to win this contest, his presence would reveal something important. Labour is no longer only asking whether it should move left or right. It is also asking whether it can find someone who sounds serious, patriotic and practical without sounding like another cautious administrator.

The forecast is that Burnham wins if he takes Makerfield before the contest begins. If Burnham cannot stand, Rayner becomes the most likely winner. Streeting remains a serious contender if Labour MPs choose discipline over renewal, while Carns becomes possible if the party wants a wildcard who can speak to security, patriotism and Reform-facing voters, especially if other candidates decide not to stand.
It should also be noted that the Labour hard left (including the Bennite tradition from which Jeremy Corbyn emerged) does not appear to have an obvious candidate capable of challenging Starmer. Figures such as Diane Abbott and Rebecca Long-Bailey remain in Parliament, but the left of the Parliamentary Labour Party is too small to shape the contest alone. This is striking, given that a significant part of Labour’s lost support appears to have moved leftwards, particularly towards the Green Party, now headed by Zack Polanski. Any new leader must be attractive enough to these voters in order for Labour to regain support and re-establish the Labour Party as the dominant part of the left.
Despite much of the lost support moving towards the left, a smaller but meaningful shift has been towards the far-right Reform Party lead by Nigel Farage. So far, attempts by the current administration to claw this support back have failed.

So if Starmer does fall, Labour will not only be choosing a new leader. It will likely be a shift of in the balance between the wings of the party. The question is in which direction, and how will the public and markets alike respond to the new prime minister.
With Streeting having already resigned, his delay in declaring his challenge is likely not one of kindness but one of a lack of assured support among his fellow MPs. It is undoubtedly in his interest to trigger the process before Burnham is able to gain his seat, which is likely in June or July.

If the leadership contest is delayed beyond this date, Burnham is the clear favourite. A rushed process may however yield surprises in both who reaches the 81 MP threshold, and the eventual vote of the Labour party membership.
It remains unclear whether a leadership challenge will be mounted whatsoever; if so, when is as difficult a question as if it will happen.

Candidates themselves may favour a general election if polling for Labour improves, allowing them to truly craft policy in their own vision. Yet, this may be the exact motivation for MPs not to trigger a leadership challenge in the first place.