Morgan McSweeney out, what next for Sir Keir Starmer?

Sir Keir Starmer’s position as Labour leader is looking increasingly precarious following the departure of his key aide Morgan McSweeney.

With fury over his handling of the Peter Mandelson scandal coming on top of dismal opinion poll ratings which have left MPs fearing for their seats, the Prime Minister’s grip on power appears to be slipping.

But a Labour prime minister has never faced a formal leadership challenge and there is a high hurdle to clear for any rival seeking to oust Sir Keir.

Here the Press Association looks at the ways in which Sir Keir could be ejected from No 10 and the potential candidates to replace him.

– Sir Keir won a landslide majority less than two years ago, why is he in jeopardy?

Poll ratings for both Labour and Sir Keir personally have plummeted, with MPs looking nervously at the rise of Reform UK on the right and the increased prominence of the Greens on the left.

A series of policy missteps and U-turns on issues including the winter fuel payments, welfare reforms and mandatory digital ID, along with the continued problems of English Channel migrant crossings and sluggish economic growth have eroded Labour’s support and damaged relations between No 10 and MPs.

The fallout from the decision to appoint Lord Mandelson as ambassador to the US, his subsequent sacking and the ongoing revelations over his links with paedophile financier Jeffrey Epstein have added to Labour’s sense of gloom.

– So are Sir Keir’s days in No 10 numbered?

The departure of chief of staff Mr McSweeney means Sir Keir, for the first time in his Labour leadership, is without his key lieutenant and the man credited with masterminding his landslide election victory.

Sir Keir’s authority has been severely damaged over the Mandelson row but even if he survives the furore, the coming weeks and months do not look any easier for Sir Keir.

A by-election in the previously safe Labour seat of Gorton and Denton on February 26 could see either the Greens or Reform claim victory in Greater Manchester.

May’s elections could see Labour lose control in Wales – one of its traditional heartlands – for the first time, English council contests also appear difficult, while in Scotland Anas Sarwar is battling to defy the slump in Labour’s UK popularity.

A bloodbath at the ballot box in those contests could be the trigger for a move against Sir Keir.

– So how could a leadership challenge work?

There is no formal confidence vote procedure to oust a Labour leader. Any challenger to Sir Keir would instead require the support of 80 MPs – 20% of the party in the Commons – to trigger a contest.

Allies of the Prime Minister have insisted he would fight any challenge, but for a rival to get that level of publicly committed support would make it incredibly difficult for Sir Keir to continue.

A more likely exit route might be for Sir Keir to quit if enough senior Labour figures privately tell him they can no longer support him.

– Who might succeed Sir Keir if he goes?

Unlike Sir Tony Blair’s exit from No 10, when Gordon Brown was the clear candidate to replace him, there could be a bruising battle for the leadership.

Former deputy leader Angela Rayner enjoys significant support within the party but is still awaiting the findings of an HMRC review into her failure to pay the correct stamp duty on the purchase of a flat in Hove, the row which triggered her resignation from the Government.

Health Secretary Wes Streeting is a confident media performer with support on the right of the party but his barely concealed leadership ambitions have ruffled feathers in Westminster.

Another candidate from the right of the party could be Home Secretary Shabana Mahmood but, as with Mr Streeting, the wider membership could favour someone closer to the left.

Former leader Ed Miliband could be that candidate, although the Energy Secretary’s previous time at the top of the party ended in the 2015 election defeat and he has publicly played down any desire to return to the job.

Whenever Labour leadership questions are raised, Andy Burnham’s name is mentioned as a possible answer.

However, the Greater Manchester mayor’s route back to Parliament through Gorton and Denton was blocked by Labour’s national executive committee, so he may be forced to watch any contest from the sidelines.

Defence minister and former Royal Marines colonel Al Carns has been mentioned as a possible breath of fresh air, but he has only been in the Commons since 2024 and replacing a leader criticised for a lack of political nous with a relative newcomer – however compelling their backstory – would be risky.

Labour could instead turn to a political veteran such as Foreign Secretary Yvette Cooper or Defence Secretary John Healey in an attempt to steady the ship.