West requires the support of 81 MPs, representing 20 percent of the PLP, to kickstart a contest.
She said she wants to “give a deadline” of Tuesday morning to avoid the challenge going “on and on,” because “sometimes these things fizzle out.”
West’s challenge would be a blow to Greater Manchester Mayor Andy Burnham’s leadership ambitions as he does not sit in the House of Commons and would not be able to be a candidate in an immediate contest.
Health Secretary Wes Streeting and former Deputy Prime Minister Angela Rayner, both sitting MPs, are also expected to stand if a leadership contest is triggered.
West also left the door open to abandoning her bid altogether: “If suddenly [Starmer] gets the bit between his teeth and I can see some more fight, then things might change.”