Penny Mordaunt is under pressure to pull out of the Tory leadership race to allow Rishi Sunak a clear path to victory.
The former chancellor has now amassed the support of 180 Conservative MPs — more than half of the parliamentary party.
To get on the leadership ballot candidates need to secure the backing of 100 MPs by 2pm today.
Mordaunt, who is Sunak’s only rival after Boris Johnson withdrew from the race yesterday, is trailing behind with the public support of fewer than 30 MPs.
However, Mordaunt’s campaign spokeswoman insisted she was “getting the numbers” and that she was “in it to win it”.
And Andrea Leadsom, who ran against Theresa May in 2016 and is supporting Mordaunt, said there was “absolutely no chance” she would step out of the race.
One hope for Mordaunt’s team is that Johnson’s supporters fall behind her in a bid to stop Sunak from becoming leader.
Leadsom also said it was “really important” that there was a “contest” and that the party “must give people a choice”.
There is tension within the Conservative Party over how the race is being conducted.
If Mordaunt fails to reach the 100 MP barrier, Sunak will be declared party leader and prime minister without a contest.
If Mordaunt does get the numbers, MPs will then decide which of the two candidates they prefer in an “indicative” vote.
If both decide to continue, the contest then goes to the party grassroots.
Tory party members will vote online to decide the outcome with the result due on Friday.
Some fear that that with such a high number of nominations required to get on the ballot, party members are being denied a real choice over who their next will be.
Others are happy to see an uncontested coronation in the interests of speed and stability.
Many also want to avoid a repeat of Liz Truss’s leadership — where party members approved of her but MPs did not.