The Mandelson Scandal: Can Morgan McSweeney’s Sacrifice Save Keir Starmer?
The political crisis surrounding Peter Mandelson’s appointment as Britain’s ambassador to the United States has reached a remarkable stage. Keir Starmer’s former chief of staff, Morgan McSweeney, has effectively stepped forward to accept responsibility for one of the most damaging decisions of the Prime Minister’s government. His message to MPs was blunt: he advised Starmer to appoint Mandelson, he was wrong, and he accepts that responsibility. Yet his testimony may have done something more complicated than simply ending the controversy. While McSweeney has taken a significant share of the blame, his evidence has also raised fresh questions about what Starmer knew, what officials knew and whether the Prime Minister’s office treated security vetting with sufficient seriousness.
Appearing before the Foreign Affairs Committee, McSweeney described Mandelson’s appointment as a “serious error of judgment”. He said that Starmer had relied on his advice and that he “got it wrong”. At the same time, he insisted that he did not instruct officials to ignore national-security procedures, ask for checks to be skipped or demand that Mandelson’s vetting be cleared “at all costs”.
That distinction lies at the heart of the political battle. McSweeney is accepting responsibility for recommending Mandelson, but he is not accepting responsibility for manipulating the security-vetting system. In doing so, he is protecting an important part of Starmer’s defence: the argument that the appointment was a catastrophic error of judgment rather than a deliberate attempt by Downing Street to override national-security safeguards.
The problem for Starmer is that other evidence presented to MPs paints a less comfortable picture.
Sir Philip Barton, the former permanent secretary at the Foreign Office, told the committee that Mandelson’s links with Jeffrey Epstein were already regarded as a serious concern before the ambassadorial appointment. Barton described the appointment as having more red flags than any other he had encountered and said that Downing Street appeared “uninterested” in the security-vetting process. He also said that he had been presented with the decision and told to get on with it, while arguing that the Prime Minister had been made aware of the risks.
This creates two competing narratives.
The first is the one McSweeney is presenting: advisers made a bad political judgment because they believed Mandelson’s diplomatic experience and relationships could serve the national interest. The full extent of his relationship with Epstein was not understood, and the appointment therefore turned into a disaster once additional information became public.
The second is far more damaging to Starmer: Downing Street knew that Mandelson presented serious security and reputational risks, but nevertheless pushed ahead with the appointment and failed to give the vetting process the importance it deserved.
Determining which account is closest to the truth is crucial because the issue is not merely whether Starmer chose the wrong person. Governments make bad appointments. Ministers and prime ministers make errors of judgment. What distinguishes an ordinary political mistake from a constitutional and administrative scandal is the question of whether established safeguards were respected.
Mandelson was an extraordinary choice even before the later revelations. He was one of the most experienced and influential figures in modern Labour politics, but he was also deeply controversial. His political career had been marked by two resignations from government during Tony Blair’s premiership, while his relationship with Epstein created an additional and profoundly serious reputational problem.
McSweeney told MPs that his understanding of Mandelson’s relationship with Epstein at the time was very different from what later emerged. He said the full revelations were “way, way, way worse” than he had expected and described discovering the details as “like a knife through my soul”.
His emotional response is significant because it helps explain why he has decided to accept personal responsibility. McSweeney resigned from his position earlier in 2026 after becoming embroiled in the controversy. By taking the blame, he is attempting to draw a line under the question of who was responsible for recommending Mandelson.
But political accountability does not always work so neatly.
A chief of staff can recommend an appointment, but the Prime Minister ultimately has responsibility for decisions made in the name of the government. Starmer was not an inexperienced backbench politician when Mandelson was appointed. He was Prime Minister of the United Kingdom and therefore ultimately responsible for the appointment of an ambassador to Washington.
This is why the phrase “the Prime Minister relied on my advice” is both helpful and dangerous for Starmer. It suggests that McSweeney was influential, but it also reminds the public that Starmer made the final decision.
The issue becomes even more sensitive because of the timing. Mandelson was appointed in late 2024, shortly after Donald Trump won the American presidential election. McSweeney told MPs that Mandelson’s diplomatic experience and political relationships made him seem particularly valuable at a moment when Britain urgently needed a strong relationship with the incoming Trump administration. He also acknowledged that Mandelson might not have been appointed had Kamala Harris won the election.
This reveals the strategic calculation behind the appointment. Mandelson was not chosen randomly. The government believed that his experience in European politics, international trade and high-level diplomacy could help Britain navigate the post-Brexit relationship with Washington.
In political terms, that reasoning was understandable. Britain needed to establish a productive relationship with a returning Trump administration, and Mandelson had decades of experience at the highest levels of politics. The problem was that diplomatic usefulness could never remove the need for rigorous scrutiny.
A government cannot simply say that an individual is exceptionally talented and therefore worth the risk. Security vetting exists precisely because senior appointments can create risks that political advisers may underestimate.
The controversy has therefore exposed a deeper tension between political decision-making and the permanent civil service. Barton’s evidence suggested that Foreign Office officials were concerned about the appointment and the vetting process. McSweeney, by contrast, denied putting pressure on officials.
This matters beyond Mandelson himself. If senior civil servants believe that political leaders are willing to push appointments through despite security concerns, trust between ministers and officials can be badly damaged. Conversely, if politicians believe that officials can obstruct politically important appointments without sufficient justification, the relationship becomes equally problematic.
Good government depends upon both sides respecting their responsibilities.
The controversy has also produced a political victory for Starmer, at least temporarily. The House of Commons voted against referring him to the Privileges Committee over allegations that he may have misled Parliament about the appointment and vetting process. The government won the vote by 335 to 223, although 15 Labour MPs rebelled.
That result means Starmer avoids a formal parliamentary investigation of the type that could have prolonged the scandal for months. But avoiding an inquiry is not the same as eliminating the political damage.
Opposition parties will continue to argue that Starmer should have known more about Mandelson before approving his appointment. They will point to Barton’s evidence, the concerns surrounding security vetting and the extraordinary revelations about Mandelson’s relationship with Epstein.
For Labour, the political danger is especially acute because the government has repeatedly presented itself as committed to higher standards of public life. Starmer came to power promising a different style of government after years of controversy surrounding Boris Johnson. His political brand was built partly around competence, integrity and respect for institutions.
The Mandelson affair therefore strikes at the centre of that promise.
If the government makes an ordinary policy mistake, voters may forgive it. But if voters conclude that Labour ministers ignored warnings, prioritised political connections over security procedures or attempted to conceal what happened, the damage could be considerably greater.
McSweeney’s testimony may consequently help Starmer in one respect while hurting him in another. By saying “I got it wrong”, the former chief of staff provides the Prime Minister with a credible explanation for how the disastrous appointment came about. But by confirming that he personally recommended Mandelson, he also establishes that the Prime Minister’s most senior adviser played a central role in the decision.
The question that remains is whether Starmer exercised sufficient independent judgment.
A Prime Minister cannot outsource responsibility to advisers. Advice is precisely that: advice. The final decision belongs to the person occupying the office.
This is the central lesson of the Mandelson affair. Governments need strong advisers, but strong advisers do not absolve political leaders of responsibility. Nor should civil servants be expected to compensate for political decisions that disregard their warnings.
The scandal has also demonstrated the extraordinary political durability of personal relationships in Westminster. Mandelson’s career has survived controversies that would have ended the careers of many other politicians. His influence came from his political intelligence, contacts and understanding of how power operates. Those qualities made him attractive to Starmer’s government. They also created the risk that political familiarity could overcome appropriate caution.
That is why the phrase “I got it wrong” may ultimately prove insufficient.
McSweeney has done something that politicians and senior officials often resist: he has accepted personal responsibility for a major mistake. That deserves recognition. His testimony was also clear that he did not believe the vetting process should ever have been circumvented.
But accountability cannot stop with the first person willing to fall on his sword.
Starmer still has to answer the larger questions. Why was Mandelson considered suitable despite the concerns surrounding him? What exactly did Downing Street know about his relationship with Epstein? How were security warnings communicated? Why did senior officials believe the process was being pushed through so quickly? And did the Prime Minister properly understand the risks before making the final decision?
Until those questions are convincingly answered, the Mandelson affair will remain a political wound for the Starmer government.
Morgan McSweeney may have taken the blame, but he cannot take responsibility for everything. His resignation can demonstrate accountability; it cannot rewrite the chain of decision-making that led to Mandelson’s appointment.
For Starmer, therefore, the challenge is not simply to survive the scandal. It is to convince the public that the lessons have been learned. Britain’s most important diplomatic appointments must be based on competence, but competence cannot substitute for security, integrity and proper process.
The former chief of staff has said, in effect, that he made a terrible mistake and that the Prime Minister trusted his judgment. That may save Starmer from the immediate threat of a parliamentary investigation. But it does not remove the fundamental question hanging over Downing Street: when a Prime Minister relies on bad advice, who ultimately bears responsibility for the decision?
The answer, in any healthy system of government, must ultimately be the Prime Minister himself.