Angela Eagle will formally launch her bid to replace Jeremy Corbyn as Labour leader on Monday by outlining an “anti-austerity vision”.
In what her supporters were touting as a major speech, the former shadow business secretary will seek to present herself as a potential boss of a credible opposition party which voters could trust to run the country.
It is understood she will focus on broad points of policy and how they could be implemented, while still emphasising her left of centre credentials, because she has one eye on the possibility of an early general election.
As the duo conducted rival TV interviews on Sunday morning, Mr Corbyn said he was “disappointed” that Ms Eagle was bidding to take his post and urged her to “think for a moment” about her actions.
A bruising leadership contest has the potential to split the party, possibly literally, whatever the outcome.
Peace talks had collapsed when deputy leader Tom Watson walked away from union-brokered negotiations aimed at ending weeks of deadlock following a revolt by an overwhelming majority of Labour MPs.
Shortly after Mr Watson’s announcement, Ms Eagle said she would formally launch her leadership campaign.
The leader of Britain’s biggest trade union, Len McCluskey of Unite, branded the decision by Mr Watson to pull the plug on negotiations an “act of sabotage” and warned it could lead to a schism in the party.
On the Andrew Marr Show, Mr Corbyn claimed he had “reached out in a way no other leader has” in an attempt to unite all parts of the party.
Mr Corbyn said he expected to be on the ballot paper as the incumbent leader – an assertion disputed by his opponents.
He added: “This is the opportunity for the party to unite against what the Tories are doing, to put forward an agenda which is different to the austerity agenda being put forward by the Tories and actually gain a lot of ground.”
Ms Eagle accused him of “hiding behind a closed door” over calls for him to step down.
She insisted her bid to take over the party and oust Mr Corbyn is about uniting Labour, not splitting it.
