Andy Burnham will promise to give people “more breathing room” when he gives his first speech as prime minister outside No 10 on Monday.
He is expected to say he is “acutely conscious” of the UK’s high turnover of prime ministers – and that politics needs to be more stable and responsible.
And he is expected to characterise the moment as one of “reflection and resolution”, arguing Britain must be honest about the challenges it faces.
Burnham will officially replace Sir Keir Starmer and become the UK’s 59th prime minister – and seventh in 10 years – on Monday, following a meeting with King Charles III.
In a letter published on Sunday evening, Conservative leader Kemi Badenoch wished Burnham “every success” as prime minister, but warned he was entering office without “any clear plan”.
“You have refused calls to come to Parliament for questions from MPs, and you have not submitted yourself to serious media scrutiny,” Badenoch wrote.
“This is not a promising start.”
It also included a promise of Conservative support to cut the benefits bill, and urged the incoming prime minister to rule out any new tax rises.
The letter followed earlier remarks from Badenoch that Burnham was a “people pleaser” at a time when the country needed someone who could “take tough decisions, who can face down Labour MPs”.
Burnham was officially declared Labour Party leader on Friday following a short contest in which he was the only candidate, having secured the backing of 379 MPs.
Some opposition parties have urged Burnham to call a general election in order to ensure he has a mandate for his premiership.
However, earlier Labour’s deputy leader Lucy Powell insisted Burnham would stick to the promises made in Labour’s manifesto in the 2024 general election but will be more ambitious.
“He really understands the bigger, bolder measures that are needed to live up to the manifesto promises,” she told the BBC’s Laura Kuenssberg programme.
