THE Tory leadership contest is now unofficially under way, with Boris Johnson’s resignation setting the wheels in motion for a new prime minister to pick up the keys to Downing Street.

Johnson intends to remain in office until his successor is elected, a process which could take months, prompting a furious backlash from party grandees and political opponents over his attempt to “cling on” in No 10 until the autumn.

But with his departure firing the starting gun for a contest to replace him, attention has turned to potential successors.

According to a YouGov poll, the clear early favourite to replace Johnson among Tory party members is Defence Secretary Ben Wallace.

While Wallace has not yet announced a leadership bid, he has won admirers for his straight-talking and straightforward approach, particularly among Conservative MPs who applauded his push for increased UK defence spending.

Wallace – who served in the Scots Guards in Northern Ireland during the 1990s – was a key voice in the UK’s response to Russia’s invasion of Ukraine, with this increased exposure doing no harm to any leadership bid.

He is followed in YouGov’s poll by Trade Minister Penny Mordaunt (below), who made waves in 2019 as the UK’s first female defence secretary, before being fired by Johnson shortly after he became Prime Minister. Mordaunt reportedly has a campaign team already in place.

The National: Penny Mordaunt

Other so-called “big beasts” who have not yet announced their candidacy include Rishi Sunak and Sajid Javid, whose resignations from Cabinet on Tuesday triggered the mass exodus that ultimately fatally crippled Johnson’s leadership.

Sunak, who the YouGov poll puts in third place, was regarded as a frontrunner before his stock took a major tumble following disclosures that his wife had non-dom status for tax purposes.

He has set up a leadership campaign office in a London hotel, reports say.

The PA news agency also understands that Javid, the former health secretary, is seriously considering running, as is Transport Secretary Grant Shapps.

Shapps, who was key to the Prime Minister’s fight for survival during partygate, was among the Cabinet ministers telling Johnson to stand down on Wednesday.

Some Tories have already made their ambitions clear, with Attorney General Suella Braverman launching an unlikely leadership bid as support for Johnson crumbled around him on Wednesday night.

Previously a loyalist to the departing PM, she told ITV’s Robert Peston that Johnson had handled matters “appallingly” in recent days and that “the balance has tipped now in favour of saying that the Prime Minister - it pains me to say it - but it’s time to go”.

READ MORE: Braverman jokingly labelled ‘next prime minister’ during Commons appearance

Braverman, who was first elected as an MP in 2015, will be regarded as an outsider for the leadership given the prominence off party grandees already tipped to be running.

Staunch Brexiteer and former minister Steve Baker, a senior Tory backbencher, also confirmed that he is “seriously considering” putting himself forward for the top job, telling Times Radio that people are asking him to do so and it would be “dismissive and disrespectful” if he did not heed expressions of support – though he added that he regards the prospect with “something akin to dread”.

Foreign Secretary Liz Truss has made little secret of her leadership ambitions, with a series of high-profile interventions and photo opportunities in which she appeared to be channelling late PM Margaret Thatcher.

Truss cut short an official trip to Indonesia, saying on Twitter that Johnson had made the “right decision” to resign, adding that the upcoming Tory leadership contest required “calmness and unity”.

The National: Kwasi Kwarteng comments

Despite not routinely featuring among those tipped to take the PM’s place, Business Secretary Kwasi Kwarteng (above) said that the country needs a leader who can “rebuild trust”, and that person should take charge “as soon as practicable”.

Sir Robert Buckland, who has just been appointed the new Secretary of State for Wales, has declined to rule out running as Tory leader.

However, Deputy Prime Minister Dominic Raab is reportedly not planning to stand for the leadership.

The exact timetable for the leadership contest is agreed by the 1922 Committee and Tory Party HQ, with Conservative MPs and party members playing a decisive role in electing the next leader.

Tory MPs will whittle down the candidates to a final two through a balloting process, with party members then voting for their preferred candidate.