Transport Secretary Grant Shapps is believed to be considering a Conservative Party leadership bid as Deputy Prime Minister Dominic Raab and Michael Gove ruled themselves out of the contest, Sky News understands.
It is understood that the transport secretary is one of the first senior Conservative MPs to be seriously considering the option of standing in the upcoming race.
Former health secretary Sajid Javid, who dramatically resigned on Tuesday evening, is also understood to be deciding whether to enter the contest – according to the PA news agency.
Meanwhile Mr Raab, who stood in as acting prime minister when Boris Johnson was struck down with COVID in the spring of 2020, does not want to take on the role.
Politics live: Boris Johnson makes resignation statement to country
Former leveling up secretary Mr Gove, who was sacked by Mr Johnson last nighthas also ruled himself out of the running.
Former health secretary Matt Hancock, who quit over breaking COVID rules, is also understood to not be interested in a leadership bid.
Elsewhere, speak before Mr Johnson announced his resignationBen Wallace declined to comment on whether he would run to replace him.
The defense secretary, a frontrunner to replace Mr Johnson, was asked if he would be seeking the top job while he was on a visit to a military training area in the north of England.
“Let’s see what the prime minister says,” he said.
Sky News’ political correspondent Joe Pike understands Mr Wallace is discussing the matter with his family before deciding whether or not to make a bid.
Another senior Tory MP deciding whether to throw their hat in the ring is chairman of the influential Common Affairs Committee Tom Tugendhat.
Meanwhile, in an interestingly timed post on social media, chairman of the Northern Powerhouse Group Jake Berry said his “top priority” will always be making sure the “call for leveling up the ambition to transform the lives of people” who live in his constituency “is not lost in the noise of a leadership election.”
Earlier today, Mr Johnson resigned, triggering a leadership contest in his party.
In his resignation speech he confirmed a timetable for the process to elect a new leader will be set out next week.
Mr Johnson told broadcasters he intends to remain in Number 10 until his successor is elected, but he faces resistance to that plan from within his own party.
The timetable for the leadership contest is expected to result in a successor being in place for the party’s conference in October.
Former prime minister Sir John Major said it was “unwise and may be unsustainable” for Mr Johnson to stay this long.
Read more: Who are the next frontrunners to be PM?
Prior to Mr Johnson’s resignation, Attorney General Suella Braverman last night indicated that she would run in any upcoming contest.
Ardent Brexiteer Steve Baker has also indicated he would run.
While Business Secretary Kwasi Kwarteng also hinted that he will throw his hat in the ring.
“We now need a new leader as soon as practicable. Someone who can rebuild trust, heal the country, and set out a new, sensible and consistent economic approach to help families,” he said.
Mr Johnson has already appointed new cabinet ministers to replace MPs who quit in protest against his leadership.
These include Greg Clark as the new leveling up secretary, replacing Mr Gove and James Cleverly as education secretary – the third person to hold that role in as many days.
The new cabinet met on Thursday afternoon but no press cameras were allowed in.