Mandelson Row: Who Could Succeed Britain’s Keir Starmer If He Resigns?

Last Updated:February 09, 2026, 14:24 IST

The Mandelson controversy and the departure of his chief of staff have pushed Starmer into a leadership crisis, reviving talk of potential successors.

British PM Keir Starmer is heading into a difficult week after the resignation of his chief of staff, Morgan McSweeney, over the Mandelson scandal that triggered open unrest across Labour.

The departure of one of his most senior aides has intensified scrutiny of his leadership and emboldened MPs who were already raising concerns about his judgement. Starmer is expected to face angry Labour Party MPs as he prepares to address the Parliamentary Labour Party, under growing pressure to explain how the situation unfolded and whether he can reassert control.

How A Misjudged Appointment Put Starmer’s Leadership Under Pressure

McSweeney stepped down after taking “full responsibility" for advising Starmer to appoint Peter Mandelson, a long-established Labour grandee, as the UK’s ambassador to the United States.

“After careful reflection, I have decided to resign from the government. The decision to appoint Peter Mandelson was wrong. He has damaged our party, our country and trust in politics itself," Morgan McSweeney said in a statement.

“I advised the Prime Minister to make that appointment and I take full responsibility for that advice," he added.

Mandelson’s longstanding ties to disgraced financier Jeffrey Epstein, which continued even after Epstein’s conviction for child sex offences, turned the appointment into a political storm that has now engulfed Downing Street.

This week, Starmer is expected to confront a Parliamentary Labour Party meeting reported by the Independent as one where he will face angry MPs. Critics inside Labour argue that although McSweeney accepted responsibility, the final decision on Mandelson’s appointment was the prime minister’s.

The situation is set to escalate further. Tens of thousands of emails, messages and documents related to the appointment will be released by the government in a process expected to unfold over months. Starmer reportedly believes this material will show that Mandelson misled officials about the extent of his ties to Epstein.

Starmer on Thursday apologised to victims of Epstein for appointing Mandelson to the prestigious diplomatic post. The apology came as opposition parties called for his resignation and some Labour lawmakers questioned his judgement.

“I am sorry," Starmer said in London, addressing Epstein’s victims. “Sorry for what was done to you, sorry that so many people with power failed you, sorry for having believed Mandelson’s lies and appointed him."

The Fallout Inside Labour After McSweeney’s Exit

In responding to McSweeney’s resignation, Starmer praised his longtime adviser’s “dedication, loyalty and leadership" and said he owed him a “debt of gratitude", without referring directly to the scandal. Two senior aides, Vidhya Alakeson and Jill Cuthbertson, have been appointed joint acting chiefs of staff, but that move has not eased the wider unrest.

Labour MP Rachael Maskell called McSweeney’s departure “a start" and said, “If he hasn’t understood the seriousness of the situation, then I think he will find it very difficult to continue." Left-wing MPs including Brian Leishman, Ian Byrne and Kim Johnson have gone further, suggesting Starmer should consider resigning.

There is also pressure from unions. Fire Brigades Union general secretary Steve Wright has said Starmer should step down, while Maryam Eslamdoust stated, “There’s no case for waiting until May… It’s time to elect a new leader."

Some political voices have urged restraint, warning that leadership turmoil could destabilise the government. Starmer ally John Slinger said “the last thing the country needs is leadership speculations", and veteran Labour figure David Blunkett cautioned against “a party acting like ferrets in a sack".

What Happens If Labour Moves Against Starmer

If Labour MPs decide to challenge the prime minister’s position, the party’s rules set out a clear but multi-stage process. One-fifth of Labour’s parliamentary party — 81 MPs — must first nominate an alternative candidate from among sitting Labour MPs. If that number is reached, the challenge formally triggers a leadership ballot.

Once nominations close, any candidate who secures support from at least 20 per cent of Labour MPs appears on a wider party ballot alongside Starmer. That larger vote includes roughly 250,000 Labour Party members and affiliated supporters, such as trade unions, who would decide the outcome in a head-to-head contest.

This structure means that removing a sitting prime minister does not require his resignation. A coordinated effort among MPs can force the process to begin even if the leader insists on staying.

For Labour, the decision to trigger such a contest carries major risks: the party has only recently taken office, public confidence in political stability remains fragile, and a leadership battle could shape British politics for years if it replaces a governing prime minister mid-term.

The Potential Successors If Starmer Falls

Angela Rayner

Angela Rayner, former deputy prime minister and Labour leader, has emerged as the leading candidate. Her odds strengthened after her intervention on 4 February, which compelled the government to give up control over which Mandelson-related documents would be released. Rayner’s background and political profile give her considerable reach within the party, though she resigned from the cabinet last September after failing to pay the correct taxes on a second home.

Wes Streeting

Until this week, health secretary Wes Streeting was viewed as Starmer’s most plausible rival. But his position has weakened. The Economist reports that press rumours of a leadership bid in November — which he blamed on Downing Street’s “toxic culture" — damaged trust on both sides. This week, his willingness to defend Mandelson, whom he described in September as “not guilty by association", has also hurt him.

Andy Burnham

Andy Burnham, the mayor of Manchester, has seen his prospects weaken. His odds fell after Starmer’s allies on Labour’s Executive Committee prevented him from standing in a by-election, limiting his path back to Parliament.

Ed Miliband

Environment secretary Ed Miliband, who led Labour during its “wilderness years" in the early 2010s and now serves in the energy and net-zero portfolio, has seen his chances improve. Miliband is extremely popular among Labour members, and has previously served as Labour Leader in opposition to David Cameron, thus has leadership experience.

He has also previously resisted Mandelson’s return to front-line roles, once remarking, “All of us believe in dignity in retirement."

Shabana Mahmood

Last on the list is Shabana Mahmood, the current home secretary, who has become known for her tough positions on immigration. In 2025, she introduced the Border Security, Asylum and Immigration Act, which expanded the government’s powers to reduce illegal migration. One of its most controversial provisions, Section 52, enables the authorities to deport immigrants who commit crimes during their stay in the UK immediately, without trial and without sentencing.

Mahmood’s approach has made her popular with right-leaning voters. However, her ideological stance may limit her prospects of becoming Labour leader, as the party has historically succeeded when positioned closer to the centre rather than the right, making her overall chances relatively slim.

A Shallow Bench

Beyond these names, The Economist describes Labour’s talent pool as “remarkably shallow", suggesting there are few obvious alternatives with the stature to stabilise the party.

Where This Leaves Starmer Now

Starmer now enters a period shaped by internal confrontation, the upcoming release of tens of thousands of documents linked to the Mandelson appointment, and growing unease within Labour. The disclosures are expected to continue for months, overlapping with local elections in May, creating an extended period of scrutiny for the government.

Whether Starmer survives will depend on whether Labour concludes that replacing him restores control or risks further instability.

News explainers Mandelson Row: Who Could Succeed Britain’s Keir Starmer If He Resigns?

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