UK Labour MPs will gather amid speculation that Andy Burnham could seek to stand for a Westminster by-election and challenge the Prime Minister's authority.
The conference of Labour's north-west England MPs will see former deputy prime minister Angela Rayner tell colleagues she is supportive of allowing the mayor of Greater Manchester to stand in the Gorton and Denton constituency candidacy race, according to The Times newspaper.
Andrew Gwynne, the former MP for the Greater Manchester seat, formally quit yesterday, paving the way for a by-election to take place.
Mr Burnham, long viewed as a potential rival to the Prime Minister for the Labour leadership, now finds himself facing a short time window to decide whether to put his name forward to stand as Labour's candidate for the seat.
Applicants must put their name forward before midnight on Sunday.
But, as a regional mayor, Mr Burnham faces the extra hurdle of having to ask permission by 5pm this evening of Labour's National Executive Committee (NEC), a body whose membership includes many Starmer loyalists.
A selection process is expected to take place over the course of next week, ending with a hustings and NEC endorsement by Saturday 31 January.
Elsewhere, senior Cabinet members are set to speak at the Fabian Society's new year conference.
Health Secretary Wes Streeting, Energy Secretary Ed Miliband, and deputy Labour leader Lucy Powell - a Manchester MP - will be among those appearing at the central London event.
Several Labour MPs yesterday warned against using the NEC to block Mr Burnham from standing in Gorton and Denton.
Jo White, who chairs the Red Wall group of Labour MPs, said: "Let the north decide who their Labour candidate should be for the Gorton and Denton by-election. A London stitch-up will be a disaster for Labour."
Crewe and Nantwich MP Connor Naismith said: "Gorton and Denton deserves the best possible choice of candidates. I agree with the Prime Minister that our attention should be on delivering for the public, not speculating about future leadership contests.
"Any decision made to limit the choice would be wrong."
A member of the NEC told the BBC's Newsnight she agreed with the parliamentarians.
Gemma Bolton, a constituency members' representative on the committee, told the programme it would be "outrageous" to block Mr Burnham should he stand, adding it would "show a real weakness" in Mr Starmer's leadership.
