Ed Miliband is said to have made a major push to become Chancellor of the Exchequer under an Andy Burnham premiership.
The Energy Secretary is believed to be the favourite to replace Rachel Reeves in the Treasury should Sir Keir Starmer lose a leadership challenge to the Manchester Mayor.
Mr Miliband's special adviser has been sent to Makerfield to campaign for Mr Burnham in the upcoming by-election.
The same adviser was also sent in February to campaign in Gorton and Denton, which was won by the Greens' Hannah Spencer.
A Labour insider told The Times: "Ed is very protective of his staff. He would never lend them to other people unless he had been guaranteed a fairly significant return favour."
Other ministers have made attempts to woo Mr Burnham.
Despite allies of the Prime Minister confirming he will not join the by-election campaign, senior Cabinet members, including Ms Reeves, have not ruled out travelling to Makerfield, with MPs viewing her decision as an indicator of where her loyalties lie.
Ms Reeves was among the first Labour MPs to endorse him when running for leadership back in 2015.
Ed Miliband is said to have made a major push to become Chancellor of the Exchequer under an Andy Burnham premiership
|PA
However, Mr Burnham is also widely expected to make Lucy Powell, Labour's deputy leader, his deputy prime minister if he defeats Nigel Farage's Reform UK in Makerfield and then wins a leadership challenge.
It comes as Mr Burnham is "working on plans for first 100 days in No10" before he has even been elected to Parliament.
The Greater Manchester Mayor's team is said to be drafting an agenda for his first three months as Prime Minister.
Plans are in their infancy, according to three insiders who have worked with Mr Burnham, but will likely address England's struggling social care system.
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The Greater Manchester Mayor's team is said to be drafting an agenda for his first three months as Prime Minister
|PA
Speaking to Politico, one insider said the plans will likely include proposals to lower energy costs for UK households.
The plans are an indication of the confidence Mr Burnham's supporters have that he will become the next Labour leader.
Staff are also having to revisit historical comments made by Mr Burnham.
Four years ago, the Mayor of Greater Manchester argued it is a "minority view" female-only toilets should be exclusive for biological women.
Andy Burnham pictured at Manchester Pride last year
| WIKIPEDIA / RATHFELDERThe comments came before the Supreme Court unanimously ruled a "woman" and "sex" under the Equality Act 2010 exclusively apply to the biological sex assigned at birth.
The Makerfield by-election candidate dismissed gender-critical activists as "supposed feminists" trying to stir up "culture wars" by asking for protections in such spaces.
It threatens to reignite Labour's "woman problem", which tormented Sir Keir Starmer and other senior party members as they previously struggled to define what is meant by being a woman.
Opposition Assistant Whip Rebecca Paul said Mr Burnham is "still trapped in the ideological bubble of 2020".
In April 2025, the Supreme Court ruled the term 'woman' in the Equality Act was defined by biological sex
| GettySpeaking to GB News, the MP for Reigate said: "Andy Burnham is still trapped in the ideological bubble of 2020 while the rest of the country has moved on.
"Women do not have penises, men should not be in women’s toilets, and politicians who once pretended otherwise should at least have the honesty to admit they got it wrong.
"It will surprise absolutely no one that Burnham backed self-ID. What is extraordinary is that so many Labour politicians still seem incapable of admitting it was a catastrophic mistake.
"Women’s rights, privacy and safety were treated as an inconvenience to an ideology completely detached from reality."
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