Losing a key by-election would be “curtains” for Keir Starmer and could mean Andy Burnham’s “time will have come”, a former Shadow Cabinet member has said.
Diane Abbott, a close ally of Jeremy Corbyn, warned Mr Starmer that Labour must win the looming Batley and Spen contest, triggered by MP Tracy Brabin’s election as West Yorkshire Metro Mayor.
Ms Abbott signalled that the party’s left could row in behind Mr Burnham, the Greater Manchester Metro Mayor, if he ran for the leadership again.
The so-called "King of the North" said he would not be challenging Mr Starmer for the leadership "any time soon" - and he doesn't have a parliamentary seat - but he made it clear he could put himself forward.
It comes amid recriminations over Labour's defeat in the Hartlepool at the hands of the Tories earlier this month.

Mr Starmer is under pressure to hold Batley and Spen, which has been Labour since 2007, but Ms Brabin kept in 2019 with a slim majority.
Writing for the Guardian, Ms Abbott said: "This West Yorkshire constituency has different demographics from Hartlepool.
"Support from the large minority ethnic electorate may enable the party to hold the seat and Starmer to hang on as Labour leader.
"But if Labour loses again, it must surely be curtains for him. And then, it may be that Andy Burnham’s time will have come.”
A Shadow Cabinet source dismissed her comments, saying: “Yet again, sections of the Labour Party at great pains to remind us that they desperately want Labour to lose.”
No date has been set for the by-election but late July is thought to be under consideration.
Kim Leadbeter, the sister of murdered MP Jo Cox, has announced she will put herself forward as a Labour candidate.
Ms Leadbeater, who established the Jo Cox Foundation in honour of her sister, said she would take her "more in common" message into the campaign if selected by Labour.
She told the Spenborough Guardian: "Anyone who knows me or has met me knows that I'm very much my own person. I'm not Jo.
"I've got my own views, my own priorities, my own ideas and dreams for the future of this area."

The party's ruling National Executive Committee will draw up a shortlist on Saturday and members choosing the final pick on Sunday.
Others rumoured to be interested in standing include Paula Sherriff, the former Labour MP for Dewsbury.
It is understood the selection could have been carried out sooner, but the chaos surrounding the sacking of Angela Rayner as party chairman is thought to have slightly delayed the process
The Tories have selected Leeds councillor Ryan Stephenson to contest the West Yorkshire seat.