Keir Starmer’s former right hand man has admitted that Labour failed to prepare for power before winning the 2024 general election. Morgan McSweeney, the Prime Minister’s ex-chief of staff, conceded the ruling party had not given enough thought to how the world had changed since Labour was last in office. In his first media interview, he said: “We didn’t prepare enough for what kind of world we were going to. We are now in a very different era than when Labour was last in government.

“I think we didn’t have enough conversations at the top of the party about what that meant, how to prepare for it, what that meant for the state. You have to deliver quite quickly for people, for them to see the change quickly. And I think we didn’t come in with enough of a theory about how we would do that.”

Mr McSweeney, who quit earlier this year over his role in Peter Mandelson’s appointment as the UK’s ambassador to the US, said he was “still processing” Sir Keir’s political demise but identified a lack of preparation as a key factor in the government’s early troubles, adding that Labour’s time in opposition “went quickly”.

The former aide said that there had been a widespread expectation that Labour would require at least two elections to return to power after its crushing defeat in 2019, and “quite a lot of people” thought it needed a plan for defeat rather than victory in 2024.

He recalled that during planning meetings early that year, he “did start to realise that we hadn’t done enough to prepare for government”.

Mr McSweeney said Labour should have been “way more optimistic when we started”.

The party chose to focus on the state of the nation’s finances that it had inherited from the Tories.

He admitted an early decision to remove winter fuel payments from millions of pensioners, a policy on which it would later U-turn, had been a mistake and had “defined the government in a way that did us a lot of damage”.

He said it was not a mistake to mean-test winter fuel payments so that better-off pensioners did not receive them, but added the threshold for claiming them had been set at “too low a level”.

He also admitted there was “no question” the party had been damaged by an early row over freebies given to ministers by donors.

Sir Keir himself had accepted thousands of pounds’ worth of clothing and spectacles in opposition.

Speaking to the BBC, Mr McSweeney also said he thought Andy Burnham, Sir Keir’s expected successor, was the right person to replace the prime minister as Labour leader, adding: “I feel optimistic about it”.

Mr McSweeney took on the chief of staff role three months after Labour’s return to office, replacing civil servant Sue Gray, who was appointed the year before the election and tasked with leading preparations for government.

Asked about Gray’s role in the run-up to taking power, he replied it was “not about one individual”, adding: “When I say we weren’t prepared, I really do mean the Labour Party more generally”.

He added: “I take my own responsibilities for that, rather than blaming one person.”