Keir Starmer is starting a new week without his aide by his side.
Morgan McSweeney, the Prime Minister’s former chief of staff, quit his role over the appointment of Peter Mandelson as US ambassador.
The senior No 10 adviser said he takes “full responsibility” for advising Mandelson’s appointment and stepped down after his role became increasingly untenable.
Pressure continues to mount on the prime minister over the scandal, which has arisen following the release of emails which appeared to show the true extent of Mandelson’s ongoing relationship with convicted child sex offender Jeffrey Epstein.
McSweeney resigned on Sunday, saying he took “full responsibility” for advising Starmer to appoint Mandelson, who had been a close ally and political mentor.
He said the decision had “undermined trust in Labour, the country and politics itself and it was the honourable course for him to go.”
Mr McSweeney became the prime minister’s chief of staff in October 2024, following Sue Gray‘s resignation from the role less than four months into the job. She said her position "risked becoming a distraction" to the government.”
Often described as Labour’s election guru, Mr McSweeney was previously seen as the mastermind behind Sir Keir’s succession from Jeremy Corbyn and the party’s landslide victory on July 4.
As one of the PM’s closest aides, Mr McSweeney held enormous influence and at one point was one of the most power government figures in the country.
Here is all we know about Morgan McSweeney:
The path to No 10
Mr McSweeney cut his teeth in local government. In 2006 he organised Labour’s successful campaign to seize control of Lambeth council from a Tory-Lib Dem coalition. He acted as the chief of staff for then council leader (and now the Environment Secretary) Steve Reed.
During his time at the London borough he is said to have led the revolt against local far left factions. It is where Mr McSweeney met his wife Imogen Walker, then a Lambeth councillor and now Labour MP for Hamilton and Clyde Valley.
His campaign work also helped see off the threat from the British National Party (BNP) in Barking and Dagenham. Between 2008 and 2010 Labour was fighting a battle against the far right who held a dozen seats on east London council.
Mr McSweeney was on the frontline as Labour adopted an election strategy focused on patriotism and tackling crime and antisocial behaviour to force out the BNP.
He later became head of the Labour group at the Local Government Association and in 2015 ran now Work and Pensions Secretary Liz Kendall’s unsuccessful bid to lead the party.
Ms Kendall received less than five per cent of the vote in a the leadership election where Jeremy Corbyn stormed to victory.
He helped start the Think Tank Labour Together where he served as director before joining Sir Keir’s team in 2020.
In Opposition
When Sir Keir became leader of the opposition Mr McSweeney oversaw Labour’s campaign operation.
He set a focus on winning back former red wall constituencies and the swing seats where Brexit-backing voters had abandoned the party in favour of Boris Johnson’s Conservatives at the 2019 election.
Labour rebranded with Union Flag logos, while the national anthem was sung at the party conference in a bid to reassure patriotic voters.
At the general election last year, the party won a huge majority of 174 seats on less than 35 per cent of the popular vote.
Relationship with Sue Gray
Sir Keir’s first 100 days in government were plagued by infighting and a scandal over a number of freebies accepted by the PM and his senior ministers.
At the same time it emerged that there was fiction between Mr McSweeney and Ms Gray in Number 10.
Ms Gray’s appointment to become the PM’s most senior political aide was controversial. She had been the senior civil tasked with writing the Partygate report, which was instrumental in bringing down Boris Johnson’s government.
Unflattering briefings about Ms Gray appeared in the press almost as soon as Sir Keir took power. There were rumours Mr McSweeney had been blocked from getting security briefings by the PM’s chief of staff - claims Whitehall officials vehemently denied.
However some were said to have found Ms Gray’s “centralisation” of government frustrating.
Announcing her resignation Ms Gray said it had been an honour to "play my part in the delivery of a Labour government", both in opposition and in Number 10.
"However in recent weeks it has become clear to me that intense commentary around my position risked becoming a distraction to the government’s vital work of change," she said.
"It is for that reason I have chosen to stand aside, and I look forward to continuing to support the prime minister in my new role."
