Ed Miliband is "on manoeuvres to topple" Sir Keir Starmer as Labour's civil war deepens, according to party insiders.
Senior Labour sources told The Sun he is plotting to "destabilise" the Prime Minister just one week before the Labour party conference in Liverpool, which has been described as "make or break" for Sir Keir.
One source said: "Everyone thinks Ed is plotting. Keir has been so loyal to Ed.
"Now, at the first moment the operation is creaking, Ed is out manoeuvring against him.
"It is ugly stuff."
During his recent reshuffle of the Cabinet, it is believed that the Prime Minister tried to move Mr Miliband to become Housing Secretary.
However, a person close to those involved said Mr Miliband "went crazy" and was "really, really angry".
Ed Miliband is said to be working to topple the Prime Minister
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The crack between the two increased when Mr Miliband became the first Cabinet minister to support Lucy Powell in her bid for the Labour Party deputy leadership job.
In recent weeks, Ms Powell has been a vocal critic of the Prime Minister after she was sacked during the reshuffle.
In her race for the deputy job, she is up against No10's pick, Bridget Phillipson.
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It is said that Ed Miliband wants to retake his position as Labour leader
|PA
Another Labour frontbencher told The Sun: "Everyone knows Ed is out and plotting.
"But if people think the answer to a mid-term wobble in the polls is to bring back a man who lost an election when he was leader last time, they have gone mad."
Mr Miliband was Labour leader from 2010 to 2015, when he quite after losing the general election to David Cameron.
Ed Miliband quit as Labour leader in 2015 after losing the general election to David Cameron
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A Labour MP said: "Ed is setting himself up as the poster boy of Labour's 'Soft Left' faction.
"Some are actually starting to talk about the possibility he could come back as leader is Keir Starmer falls."
However, a source close to Mr Miliband insisted: "This is nonsense."
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