Rishi Sunak already has the backing of 142 MPs.
Britain's former finance minister Rishi Sunak could end up becoming the country's next prime minister if his opponent Penny Mordaunt fails to win the backing of 100 MPs by today. Sunak already has the backing of 200 members of the parliament.
Penny Mordaunt currently has the support of 29 MPs.
Boris Johnson, who was ousted from the premiership in July and left office in September, pulled out of the race just hours before the deadline to file their nomination.
If Mordaunt fails to garner the support of 100 MPs by 2 pm local time (6.30 pm IST) on Monday, Rishi Sunak would automatically become the prime minister.
Under rules announced on Thursday, a maximum of three Tory MPs will be able to run, as the party has set a threshold of 100 MPs for candidates to even get on the ballot paper, and there are a total of 357 MPs in the party.
The final two candidates will face an expedited online vote by around 170,000 Tory members, with the new leader elected by next Friday.
Rishi Sunak announced his official candidacy yesterday, saying that he aims to fix the economy, unite the party and "deliver for the country".
Johnson and Sunak met last night amid speculation of a deal between the two, despite the bitterness left by Sunak's role in Johnson's downfall as prime minister.