From Svengali to sacked: Who is Morgan McSweeney, the prime minister's departed chief of staff?

For those wishing to understand the Starmer project, it is hard to overstate how crucial a role Morgan McSweeney played.

Born in Macroom, County Cork, Mr McSweeney got his big break for Labour working at Lambeth Council with Steve Reed, the current housing secretary, who would later introduce him to the man who would go on to be Labour leader.

Working at the south London council gave McSweeney his first taste of taking on his opponents of the left - a theme that would come to define his ascent to the very top of the Labour Party.

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A central component of Labour winning back control of Lambeth in 2006 under Mr Reed was Mr McSweeney's campaign to remove all traces of the hard left from the party, which had dominated in the 1980s and 1990s under "Red" Ted Knight, who had been expelled from Labour in the 1950s as it carried out a purge of Trotskyists.

Fast forward to 2017, and Labour was under the leadership of Jeremy Corbyn - someone Mr McSweeney regarded as equally unsuited to power as the hard left figures in Lambeth.

That same year, he became director of Labour Together, a thinktank that challenged the narrative and ideology of the left under Mr Corbyn and which later helped Sir Keir win the 2020 Labour leadership election.

After running Sir Keir's leadership bid, Mr McSweeney was appointed as his chief of staff, where he was accused of marginalising the left further, for example, by hampering their ability to stand for parliament by controlling shortlists.

It was at this time that concerns about Mr McSweeney's influence and control over Sir Keir began to surface.

The criticism directed at Sir Keir was that, with his lack of political background and instincts (he did not, for instance, work his way up through the Labour Party or the trade union movement), he created a vacuum for decision-making that could be occupied for better or worse by Mr McSweeney.

It is through this lens that some have viewed Peter Mandelson's appointment as US ambassador and the subsequent scandal that resulted in him quitting the House of Lords following the release of the Epstein files.

They appeared to show that, as business secretary, Peter Mandelson forwarded sensitive market information to Epstein and that he had received $75,000 from the disgraced financier.

Lord Mandelson's representatives have been contacted for comment.

The prime minister was said to be not sold on the former spin doctor becoming his US ambassador, but that Mr McSweeney - a close ally of the Labour peer - pushed for his appointment.

In light of the scandal surrounding Lord Mandelson anger against Mr McSweeney intensified, as did the political pressure to remove him.

But Number 10 stuck by Sir Keir's chief of staff, with a spokesperson saying the prime minister had confidence in Mr McSweeney even as the scandal deepened.

Even before that, Mr McSweeney became the target of frustration and anger among Labour MPs at the botched handling of welfare reforms.

He was accused of treating MPs with disdain and of failing to grasp the extent of their concerns. In the end, it was only with the involvement of now departed Angela Rayner that MPs eventually decided to back a much watered-down version of cuts.

And although these were attributed to "allies" of Sir Keir, Labour MPs demanded his head after briefings to journalists that the prime minister was facing an imminent coup attempt by Health Secretary Wes Streeting, which plunged No 10 into crisis.

The real power behind the throne?

Despite his success in making Labour electorally viable after years in opposition, Mr McSweeney encountered multiple bumps in the road.

The most major was the fallout of the 2021 Hartlepool by-election, which saw the Tories win a seat that had been under Labour's control since it was created in the 1970s - a moment so devastating for the party that Sir Keir later admitted he considered resigning.

The Hartlepool by-election was also a major setback for Mr McSweeney, who was demoted as Sir Keir's chief of staff back to a campaign role.

For his critics, the by-election saga was proof that Mr McSweeney, for all his campaigning prowess, was not suited to the role of chief of staff, with all of the administrative responsibilities and management skills required.

However, it did not stop Sir Keir from moving Mr McSweeney back into the role to replace Sue Gray - the partygate investigator who was appointed shortly before Labour's election win - following a bitter power struggle inside Number 10.

Again, for critics of the prime minister's operation, this episode stands out as one that revealed the extent of Mr McSweeney's influence over Sir Keir.

The brutal nature of Ms Gray's departure, which came after weeks of anonymous negative briefings in the newspapers, seemed to some to provide a warning about Mr McSweeney's ruthlessness.

Ms Gray was a close ally of Sir Keir and his pick for chief of staff - so for some, the way she was discarded acted as a foreshadowing of what the prime minister could expect to face if he ever found his leadership in peril - as he does now.

The danger for Sir Keir is that he now has two former allies with an axe to grind - a spin doctor of the past and one of the present.

(c) Sky News 2026: From Svengali to sacked: Who is Morgan McSweeney, the prime minister's departed chief of staff?