Shadow foreign secretary Emily Thornberry has confirmed she is running to be the next leader of the Labour Party, hours after shadow Brexit secretary Sir Keir Starmer revealed he is "seriously" considering the fight.
Ms Thornberry, one of Jeremy Corbyn's closest allies, made the announcement in an article for the Guardian, telling readers she is already experienced in debating Boris Johnson from when he was foreign secretary.
She said the next leader should be elected for their "political nous and strategic vision", rather than their "position on Brexit, or where they live in our country".
In her article she revealed she warned Mr Corbyn it would be an act of "catastrophic political folly" to back the doomed election.
By throwing her hat into the ring she has become the first Labour MP to confirm she wants to lead the party, but there is speculation surrounding several others.
She is likely to face fierce competition, with shadow cabinet members Rebecca Long-Bailey and Angela Rayner also believed to be considering their chances.
But those Labour big-hitters could be surprised by several backbenchers, including 2015 contender Yvette Cooper, Jess Phillips, and Lisa Nandy, who may also stand.
The shadow cabinet members and the backbenchers represent two different directions of travel for the Labour Party, with those close to Mr Corbyn likely to carry on his message and the others likely to steer the party away from his agenda.
Sir Keir contradicted the party's most successful leader Tony Blair when he said Labour should not "oversteer" away from Mr Corbyn's radical left wing agenda.
He claimed Mr Corbyn was right to make Labour an "anti-austerity" party and insisted the party should not "lurch away from that in the wake of this" election defeat.
His intervention came as ex-prime minister Blair made a scathing assessment of Mr Corbyn's leadership, saying he turned it into a "glorified protest movement, with cult trimmings, utterly incapable of being a credible government".
Mr Blair said Labour had become "marooned on fantasy island" in the left of politics and she doubts any prospective leader can “take it to the mainland”.
In an attempt to distance himself from Mr Blair, Sir Keir said the party must not go back to "some bygone age".
Some commentators have said Sir Keir is positioning himself to be closely aligned with the Corbyn message, in a bid to attract swathes of left-wing Labour members.
But Sir Keir, who does not want to be thought of as a torchbearer of Corbynism, said: "I don't need anybody else's name tattooed to my head to make a decision on this."
Sir Keir said: "I fundamentally believe that the move in 2015 by the Labour Party to a position of anti-austerity, anti-cuts to our public services, was right."
"What Jeremy Corbyn brought to the Labour Party in 2015 was a change in emphasis that was really important - a radicalism that matters," told the BBC Radio 4 Today programme.
"We need to build on that rather than simply say 'Let's now oversteer and go back to some bygone age'. We need to build on that radicalism.
"What we mustn't do is say now, because we have lost in 2019, that move to an anti-austerity party has got to be rejected and we go back to some other political place that we were in in the past."