Angela Eagle is to delay her expected leadership challenge to Jeremy Corbyn, Labour sources have said.
The former shadow business secretary had been expected to declare that she was going to run as a “unity candidate” at a 3pm news conference.
However sources said she had decided to hold off because of the turmoil engulfing the Conservatives following the shock withdrawal of Boris Johnson from the leadership race.
“She is still up for it. She has the signatures,” one source said, referring to the 50 nominations from Labour MPs and MEPs needed to mount a challenge under party rules.
Ms Eagle is expected to pledge to reunify the fractured party, which has been locked in a vicious internal battle since the weekend, when Mr Corbyn sacked his shadow foreign secretary, Hilary Benn, for plotting against him.
Earlier Labour's deputy leader, Tom Watson, became the most senior party figure to call on Mr Corbyn to resign, intensifying the pressure on the leader on a day of drama in Westminster.
“It’s a great tragedy,” Mr Watson told the BBC .
“He does have a members’ mandate, but those members who join a political party know that you also need a parliamentary mandate if you are to form a government.
“You have to have the authority of the members and your members of parliament, and I’m afraid he doesn’t have that with our MPs.”
Mr Watson said he would not stand in any leadership election himself, apparently clearing the way for Ms Eagle to mount her challenge.
However, Ms Eagle's local members may oppose her candidacy. The deputy chair of the Wallasey constituency Labour party, Paul Davis, told BBC North West Tonight: "Jeremy Corbyn hasn't been given a chance to be a good leader.
“If you are being stabbed in the back all the time by your own people on the Labour benches it’s very hard to get your message across. So yes, I do think he’s a good leader.”
Mr Watson said he had attempted to discuss the leadership issue with Mr Corbyn, after his predecessors Gordon Brown and Ed Miliband added their voices to those calling for him to go, but the Labour leader had refused to engage in conversation about his future.
“I’m afraid Jeremy was not willing to discuss that with me,” he said. “I’m assuming that he remains in office. That’s where the situation stands.”
Earlier, Mr Corbyn’s spokesman insisted that he would stand again if challenged, and would expect his name to appear automatically on the ballot.
Mr Watson said: “I just think he feels very strongly that he has that mandate from the members. He holds less weight on parliamentary politics, and that’s where he is.
“He’s obviously been told to stay by John McDonnell [the shadow chancellor] and his team, and they’ve decided they’re going to tough this out. It looks like the Labour party is heading for some kind of contested election.”
‘Anti-Semitism’
Meanwhile, Labour MP Ruth Smeeth has claimed the party “cannot be a safe space” for British Jews after Mr Corbyn failed to intervene when she was verbally abused by one of his grassroots supporters at a press conference.
Ms Smeeth, who is Jewish, said Mr Corbyn had shown a “catastrophic failure of leadership” and must immediately resign to make way for “someone with the backbone to confront racism and anti-Semitism”.
Marc Wadsworth, who runs Momentum Black Connexions, accused the Jewish MP of "working hand in hand" with the Daily Telegraph during a tirade at the event in central London.
A clearly upset Ms Smeeth stormed out of the event, which had been staged to launch a report into anti-Semitism in the party.
She said: “I call on Jeremy Corbyn to resign immediately and make way for someone with the backbone to confront racism and anti-Semitism in our party and in the country.”
The Labour leader has insisted he condemns “any abuse of MPs of any kind” but Ms Smeeth said that under his leadership, the party “cannot be a safe space for British Jews”.
Mr Corbyn had ignored the criticism of Ms Smeeth during the event, instead focusing on the contents of the review carried out by Shami Chakrabarti.
“I was verbally attacked by a Momentum activist and Jeremy Corbyn supporter who used traditional anti-Semitic slurs to attack me for being part of a ‘media conspiracy’,” Ms Smeeth said.
“It is beyond belief that someone could come to the launch of a report on anti-Semitism in the Labour Party and espouse such vile conspiracy theories about Jewish people, which were ironically highlighted as such in Ms Chakrabarti’s report, while the leader of my own party stood by and did absolutely nothing.
“People like this have no place in our party or our movement and must be opposed.
The row overshadowed the launch of the report, which was sparked by a row over alleged racist remarks that led to the suspension of high-profile figures such as MP Naz Shah and former London mayor Ken Livingstone.
The review recommended that Labour members should not use terms such as “Paki” or “Zio” and should steer clear of invoking Hitler, particularly in debates about Israel and Palestine.
“The Labour Party is not overrun by anti-Semitism, Islamophobia, or other forms of racism,” it added.
Mr Corbyn was backed by 10 of Britain’s biggest trade unions. In a joint statement they said:
“Jeremy Corbyn is the democratically elected leader of our party who secured such a resounding mandate less than 10 months ago under an electoral procedure fully supported by Labour MPs.
“His position cannot and should not be challenged except through the proper democratic procedures provided for in the party’s constitution. We urge all Labour MPs to abide by those procedures, and to respect the authority of the party’s leader.
“The only party that can win for working people is a strong and united Labour party.”
The signatories to the statement included the general secretaries of Unite, Unison, the GMB and Ucatt.
Guardian/PA