by Conrad Landin and Luke James

An attempted Blairite coup to replace Ed Miliband with former home secretary Alan Johnson was crushed when shadow health secretary Andy Burnham threatened to mount a challenge, senior Labour sources have told the Morning Star.

Speculation about Mr Miliband’s leadership has been rife this week following briefings to newspapers from Labour MPs.

Mr Johnson, who has returned to the public spotlight after publishing his childhood memoirs, has repeatedly been named as an alternative leader.

But in a backlash from party figures who say a late challenge would damage Labour’s election chances, sources have named and shamed key players in the debacle.

One person close to party machinations said that on Tuesday evening deputy chief whip Alan Campbell attempted to gather signatures from fellow MPs calling for Mr Miliband’s resignation.

“He was canvassing for signatures in the Stranger’s Bar (in the House of Commons),” the source said.

“They decided they were going to get the names, Miliband would have had to stand down and Alan Johnson could be caretaker leader.”

They also linked Yorkshire MP Michael Dugher to the plot.

He was replaced as vice-chair of Labour’s election campaign by Miliband arch-loyalist Lucy Powell in a mini-reshuffle on Wednesday night, which sources initially said was designed to wrest control of the campaign back from Douglas Alexander, who backs Ed Balls’s “austerity-lite” strategy.

But Mr Dugher was in fact promoted to the position of shadow transport secretary, leading some sources to dispute his role in the attempted coup.

Plotters had allegedly in­­tended to confront Mr Miliband on Wednesday mor­ning, but were foiled by chief whip Rosie Winterton and a threat by Mr Burnham to stand against Mr Johnson should Mr Miliband resign.

“In these circumstances it would have to be a coronation,” said the source, suggesting that a leadership contest would be considered too messy.

One senior source in the Parliamentary Labour Party (PLP) said they could neither confirm nor deny that Mr Campbell was behind the plot.

“There’s always been disaffection in the PLP from people who supported David Miliband,” they said.

“It’s completely pointless to our candidates who are working hard to win seats and there are all these people in Westminster playing games.”

MPs Simon Danczuk and Ian Austin, who are both likely to face strong challenges from Ukip at the general election, have been named as potential sources of disquiet about Miliband’s leadership.

Sources told the Star that Mr Danczuk was unlikely to be involved in the co-ordinated challenge, but blamed him for initiating media briefings that put Mr Miliband’s leadership under the spotlight.

The parliamentary source said: “There’s a bunch of MPs in the north-west who are panicky about Ukip, and they’re starting to go on about Ed when in fact the answer to Ukip is for them to go out and do some work.”

Another senior MP told the Star: “It is true that there’s mumbling among MPs about Miliband, especially among those who have small majorities and are getting worried about the election. Simon Danzcuk falls into that group.

“But the point is that backstabbing is totally counter-productive.

“We should be pointing out that it’s David Cameron who has a leadership crisis — he’s lost two MPs to Ukip and is about to lose the Rochester by-election.”

They said the briefings were unlikely to have come from Mr Balls’s camp, saying that he “wouldn’t run against Miliband because he would be crushed.”

A spokesman for Mr Danczuk said: “Simon Danczuk is not talking to any media about the speculation around the leadership.”

Mr Campbell was not available for comment.