SIR Keir Starmer’s top aide Morgan McSweeney has today quit following days of pressure over the Mandelson scandal.
The Downing Street chief of staff fell on his sword amid demands for him to go from angry Labour MPs.
Mr McSweeney advised the PM to appoint Lord Mandelson as US Ambassador despite his well-known relationship with paedo Epstein.
His resignation will be viewed as a last-gasp attempt to save Sir Keir’s premiership that has been plunged into turmoil in recent weeks.
In his resignation letter, Mr McSweeney took “full responsibility” for the decision to appoint the disgraced Labour peer.
He said: “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.
“When asked, I advised the Prime Minister to make that appointment and I take full responsibility for that advice.
“In public life responsibility must be owned when it matters most, not just when it is most convenient.
“In the circumstances, the only honourable course is to step aside.”
Mr McSweeney said Sir Keir retains his full support and that it has been the “honour of his life” to serve as his chief of staff.
He has served as the PM’s top aide since late 2024 after replacing the axed Sue Gray in the most senior adviser role.
He masterminded Labour’s general election campaign and was credited with banishing the hard left from the party.
But Mr McSweeney has been criticised for freezing out MPs and seeking advice from figures like Lord Mandelson, with whom he was close.
In recent days there has been a groundswell of calls from Labour MPs and grandees to sack Mr McSweeney over the scandal.
Only this morning Cabinet Minister Pat McFadden said that getting rid of Mr McSweeney would not help Sir Keir.
The departing chief of staff said: “As I leave I have two further reflections: Firstly, and most importantly, we must remember the women and girls whose lives were ruined by Jeffrey Epstein and whose voices went unheard for far too long.
“Secondly, while I did not oversee the due diligence and vetting process, I believe that process must now be fundamentally overhauled. This cannot simply be a gesture but a safeguard for the future.”
Sir Keir issued a grovelling apology for hiring Mandelson, but said he was not aware of the “depth and the darkness” of his relationship with Epstein.
But ex-PM Gordon Brown warned Keir Starmer is facing a “serious” threat to his leadership, saying the Labour leader had been “too slow” to act.
And Sir Keir’s right-hand man David Lammy reportedly warned the Prime Minister against appointing Mandelson last February.
It is understood the Deputy PM David Lammy, then-Foreign Secretary, instead favoured keeping Dame Karen Pierce on as the US Ambassador.
Mr McSweeney continued: “This has not been an easy decision.
“Much has been written and said about me over the years but my motivations have always been simple.
“I have worked every day to elect and support a government that puts the lives of ordinary people first and leads us to a better future for our great country.
“Only a Labour government will do that. I leave with pride in all we have achieved mixed with regret at the circumstances of my departure.
“But I have always believed there are moments when you must accept your responsibility and step aside for the bigger cause.
“I remain fully supportive of the Prime Minister. He is working every day to rebuild trust, restore standards and serve the country.
“I will continue to back that mission in whatever way I can. It has been the honour of my life to serve.”
