UK prime minister Theresa May has set a timetable for her departure — and fired the starting gun for those jostling to replace her.
Her former foreign minister, Boris Johnson, has claimed he will be in the race to get into 10, Downing Street.
But who else is favourite to head up the Conservative Party and the UK's government? And what will each change of leadership have on the burning issue of the day, Brexit?
Boris Johnson: 2/1
According to Oddschecker, the favourite to take control of Tory leadership is Brexit campaigner and former Foreign Secretary Boris Johnson.
In Johnson's resignation letter from July 2018, he wrote that the Brexit "dream is dying, suffocated by needless self-doubt."
Johnson, 54, who also served as Mayor of London from 2008-2016, has been one of the most vocal Brexiteers from the onset.
He became the first Tory to publicly throw his hat in the ring to replace May during an appearance at a British Insurance Brokers' Association event in Manchester on Thursday.
"Of course I'm going to go for it," the BBC cited Johnson as saying on Thursday.
With the Tories sinking in the polls, the Conservatives could turn to Johnson's bullish Brexit policies to lead the party.
Dominic Raab: 13/2
Bookmakers have dubbed Esher and Walton MP, Dominic Raab, the second most likely Tory to command leadership of the party.
Raab followed David Davis as the UK's Secretary of State for Exiting the European Union before resigning from May's cabinet in November 2018, due to his disapproval over the Cabinet position on the draft Brexit withdrawal agreement.
At the time of his resignation, Raab said he could not support the PM's deal because the regulatory regime proposed for Northern Ireland presented a “very real threat” to the integrity of the UK and was also opposed to the indefinite backstop arrangement.
Raab, who studied law at Oxford and then Cambridge, played a prominent role in the Leave campaign of 2016 and has potentially candidacy has already inspired a 'Ready for Raab' social media campaign promoting the MP's claim to conservative leadership.
In leading up to the original March 29 Brexit deadline, Raab said that a no-deal Brexit scenario was not his "preferred outcome" but would rather leave the EU without a deal than filing a Brexit extension.
Jeremy Hunt: 12/1
Coming in third right behind Raab with 12-to-1 odds is current British Foreign Secretary Jeremy Hunt.
The 52-year-old MP representing South West Surrey gained national recognition for his leadership in overseeing the 2012 London Olympics, which led to his appointment as Health Secretary.
During the 2016 referendum to leave the EU, Hunt supported Britain's remain campaign.
In 2017 however, he stated that he had changed his mind and now supported Brexit, citing the "arrogance of the EU Commission" in responding to the UK government in the Brexit negotiations.
Hunt has acknowledged his party may be heading for “disastrous” European elections results due to the Conservatives inability to deliver Brexit on time. He has also said alternative options of a general election and a second referendum were "difficult."
Michael Gove: 14/1
Secretary of State for Environment, Food and Rural Affairs Michael Gove is next on the list with 14-to-1 odds to seize command of the Conservatives.
The 51-year-old MP for Surrey Heath was born in Edinburgh, Scotland and came in third place behind Theresa May and Andrea Leadsom in the 2016 Conservative Party leadership election following the resignation of Prime Minister David Cameron.
Gove was one of the first politicians to publically back Brexiteers and described his decision to campaign for Britain to leave the EU in the 2016 referendum as "the most difficult decision of my political life".
Gove, who is also an author and columnist for The Times, has recently warned hardline Tory eurosceptics that leaving the EU without a deal "wasn’t the message of the campaign I helped lead".
Gove told ITV News reporter Robert Preston on Sunday that it is in the national interest to "get Brexit over the line," and it is what the Prime Minister Theresa May needs to focus on.
Jeremy Corbyn: 20/1
The British opposition leader and leader of the Labour party Jeremy Corbyn is next in line to be the next Prime minister, with 20-to-1 odds.
As support for the Conservatives plummets, the Labour leader, whose odds were much lower a few weeks back, is now seen as a serious potential next Prime minister.
After cross-party talks with the government collapsed earlier this week, Corbyn said that his party would not support May's Brexit deal.
Penny Mordaunt: 25/1
The first woman the bookmakers are taking seriously to bid for Tory chief is current Secretary of State for Defence Penny Mordaunt.
The enthusiastic Brexiteer is being considered one of the main dark horse candidates to ascend to the top of the conservative ticket as she is one of the last remaining pro-Brexit members of May's cabinet.
Matthew Hancock: 25/1
Secretary of State for Health and Social Care, Matt Hancock is ex aequo with Mordaunt, according to oddsmaker with a 25-to-1 chance to become Tory captain.
The 40-year-old MP for West Suffolk has recently defended Theresa May over her decision to hold talks with Jeremy Corbyn to end the Brexit deadlock and said Corbyn’s support for delivering Brexit trumped other concerns about him.
Sajid Javid: 25/1
Another 25-to-1 longshot is current Home Secretary Sajid Javid. The MP for Bromsgrove in Worcestershire since the general election of 2010, Javid is also a former managing director at Deutsche Bank who was an early advocate for an EU referendum but remained a backer for the Remain campaign to the disappointment of pro-Brexit Tories.
Javid, 49, who is known to have held Eurosceptic views in the past, has made it clear since the referendum that he is sceptical of softer Brexit options such as remaining in the customs union, saying the free trade area was an “intrinsic” part of the European Union and that voters had given “clear instructions” when they voted to Leave.
Nigel Farage 25/1
Nigel Farage, the leader of the Brexit Party and a sitting MEP, is listed with 25-to-1.
His odds are sensibly higher than a few weeks ago.
Rory Stewart: 28/1
Another longshot is recently appointed Secretary of State for International Development, Rory Stewart, has served as MP for Penrith and The Border since 2010.
Stewart, 46, gained notoriety as senior collation official in Iraq from 2003-04 and for his book Occupational Hazards or The Prince of the Marshes, about his time governing in Iraq.
The Hong Kong-born, Harvard graduate said following Brexit that Britain must "make the best out of Brexit," and that the UK should be "energetic and optimistic" about their position. Stewart stressed the need to invest now more than ever in "rebuilding Britain's international position."
Andrea Leadsom 28/1
Andrea Leadsom's odds are at 28-to-1.
Leadsom was a favourite in the last Conservative leadership contest, in July 2016.
Of course, Theresa May eventually won, but could the latest furore lead to a turn in her fortunes?
Other notable long shots:
- Priti Patel: 66/1
- Jacob Rees-Mogg: 100/1
- David Davis: 100/1
- David Cameron: 500/1