Labour's Angela Eagle is expected to announce a challenge to Jeremy Corbyn's leadership of Labour later today.

The move comes after a number of unions appeared to throw Mr Corbyn a lifeline in his battle to keep his job.

The party's deputy leader Tom Watson yesterday said that he would not stand, clearing the field for Ms Eagle, a former shadow business secretary.

But in an extraordinary move Mr Watson publicly said that he had tried to tell Mr Corbyn to quit, but the Labour leader would not talk to him about the issue dominating the party.

“I’m afraid Jeremy was not willing to discuss that with me,” he said.

Mr Watson also intensified the ongoing civil war within Labour by accusing the shadow chancellor John McDonnell of refusing to allow Mr Corbyn to resign.

Mr Watson said: "He has obviously been told to stay by his close ally John McDonnell. They are a team and they have decided they are going to tough this out. So it looks like the Labour party is heading for some kind of contested election."

Mr McDonnell later acknowledged that the party was heading for a leadership election.

He insisted the Mr Corbyn was " not going anywhere" as he accused a number of MPs of “tearing the party apart”.

Earlier his predecessor Ed Miliband called on Mr Corbyn to quit saying that his position was "untenable".

Former acting Labour leader Margaret Beckett also called on him to "exercise (his) leadership and go”.

And former Labour prime minister Gordon Brown predicted that Mr Corbyn would stand down.

“I don’t think Corbyn’s going to stay, he’s going to go. He knows the parliamentary party have no faith in him,” he said.

But Mr Corbyn's team was adamant that their man was going nowhere.

They said that he would soon announce new members of his shadow cabinet, including a new shadow Scottish secretary, a post that has been empty since Sunday.

Labour sources denied reports that Scottish Labour leader Kezia Dugdale had offered to fill the role.

They said that while she had a standing invitation to attend shadow cabinet meetings an MSP would be unable to fill the Westminster role.

Sources suggested that the party was planning to "double up" a number of jobs and that the Scottish job could be shared with the Northern Ireland portfolio.

Earlier David Cameron also appeared to give a boost to Mr Corbyn.

The Prime Minister urged the Labour leader at Prime Minister’s Questions : “For heaven’s sake man, go.”

The intervention is likely only to help Mr Corbyn with the core supporters he will have to win over to keep the leadership.

As is next week’s Chilcot report, which is likely to heavily criticise former Labour Prime Minister Tony Blair’s handling of the Iraq War.

Any future Labour leadership contest could have to be conducted amid reignited anger over the events of 2003.

Many Labour MPs admit that if Mr Corbyn refuses to go and there is a leadership contest he could win.

Tens of thousands of people joined the party last summer in order to vote for the veteran socialist.

Yesterday, some Labour MPs privately said that they did not want Mr Watson to stand, for fear of losing both a leadership and a deputy leadership contest at the same time.

Sources close to the leadership were confident about their chances.

One denounced Monday's night's meeting of Labour MPs, in which they angrily pleaded with Mr Corbyn to resign, saying: "I did not know that lemmings could clap”.

Mr Corbyn also received the support of Hollywood actor Ewan MacGregor.

He used the social media site Twitter to tell Mr Corbyn: “The turncoats in your party should be ashamed of themselves. I hope you find the support you deserve.”

Last night a number of Labour figures including Mr Corbyn and Mr McDonnell addressed a rally in London urging the party not to change its leader.