Secret plans have revealed the date by which the country will have have a new Prime Minister.
Boris Johnson's successor is set to take over by September 5, according to a timetable expected to be given the green light by the 1922 Committee executive meeting at 5pm on Monday.
It comes as Foreign Secretary Liz Truss becomes the 10th MP to join the leadership race - while moments later Rehman Chishti became the 11th.
The Telegraph reports that a senior Tory source told the paper that party members will vote in a new leader within two months.
There is apparently some concern within the party, however, that more than 16 MPs could join the battle for the top spot.
These include lesser-known backbenchers such as Sir Bill Wiggin, John Baron and Rehman, who, it emerged on Friday, were thinking about standing.
Questioned over why he was considering a bid, Mr Baron said: “I would be a newcomer to the contest... I will take soundings over the weekend.”
But the senior party source told The Telegraph: “There will be a threshold so that candidates below that threshold will not be allowed to continue.
“We want to reduce the field to serious candidates and if you can't get a reasonable proportion of the party to support you, we don't want grandstanders.”
According to the plans set to be approved by the 1922 Committee tomorrow, MPs must confirm their bid by Tuesday if they want to join the race.
Although it had previously been thought that candidates would need the backing of 10 MPs to stand, it is believed the 1922 Committee will raise this to 20 MPs.
The initial round of voting will happen on Wednesday, before any candidate with 35 MPs or less will have to stand aside.
A second vote then takes place the following day, when another MP will be eliminated. Those remaining will be questioned by colleagues in private on July 18.
More rounds are set to take place on July 19 and July 20, with an MP dropped each time. Members then vote on the final two contenders.
The 11 MPs that have joined the race so far are: Foreign Secretary Liz Truss, former equalities minister Kemi Badenoc, Attorney General Suella Braverma, former health secretary Jeremy Hunt, former health secretary Sajid Javid, Trade Minister Penny Mordaunt, Transport Secretary Grant Shapp, former chancellor Rishi Sunak, backbencher Tom Tugendhat and Chancellor Nadhim Zahawi and Mr Chishti.
