Liz Truss resigned on Thursday after just over six tumultuous weeks in the top job, with a new prime minister expected to be in place by the end of next week.
The Tories are now scrambling to find a replacement, who will become the third leader in two months.
– How did we get here?
Liz Truss was elected as Conservative Party leader on September 5 and took over as Prime Minister the following day. Her premiership had barely begun when politics ground to a halt following the death of the Queen.
The pivotal event of her time in office was then-chancellor Kwasi Kwarteng’s mini-budget on September 23, which triggered turmoil in the financial markets and required an emergency intervention by the Bank of England to support Government bonds.
A chaotic party conference followed, overshadowed by a U-turn on the policy to scrap the 45p rate of income tax, with daunting poll leads for Labour adding to unease on the Tory benches.
Mr Kwarteng was sacked and replaced by Jeremy Hunt, who junked almost all of the tax cuts which had been a key part of Ms Truss’s appeal to party members.
Things seemed to have calmed down until the calamitous events of October 19.
– So what happened on Wednesday?
Ms Truss was defiant at Prime Minister’s Questions, insisting “I am a fighter, not a quitter”.
But things unravelled in dramatic fashion after that, with Suella Braverman resigning as home secretary and accusing the Government of “breaking key pledges” including on immigration policy.
On Wednesday evening, there were ugly scenes in the Commons as Tory MPs were ordered to vote against a Labour motion on fracking with some alleged to have been “manhandled”.
Chief Whip Wendy Morton was rumoured to have resigned, only for No 10 to confirm she remained in place.
– What happened then?
Pressure on Ms Truss continued to mount on Thursday, with the list of Tory MPs publicly demanding her resignation expanding.
At around noon, it emerged the embattled Prime Minister was in talks with Sir Graham Brady, chairman of the powerful 1922 Committee of Tory backbenchers, who was said to have been amassing letters of no confidence from disgruntled MPs.
Shortly thereafter, it was announced she would be giving a statement in Downing Street.
At around 1.30pm, Ms Truss stepped up to the lectern outside the famous black door and said she had told the King she was resigning as leader of the Conservative Party.
She said she recognised she “cannot deliver the mandate” which Tory members gave her a little over six weeks ago when she replaced Boris Johnson.
– What happens next?
In her brief resignation speech, Ms Truss said she will stay on as Prime Minister until a successor is chosen via a leadership election to be completed in the next week.
Sir Graham said the process will be concluded by October 28 so the new leader is in place in time for a crucial financial statement on October 31, which is intended to reassure the City of London that the Government has a plan to repair the nation’s finances.
– How will a successor be chosen?
Ms Truss’s decision to step down will trigger a scramble among Tory leadership contenders who will face a daunting task to revive the party’s fortunes.
On Thursday afternoon, Sir Graham declared the parliamentary stage of the contest had begun, with nominations open.
Candidates will need a minimum of 100 colleagues nominating them to proceed to the ballot.
“We fixed a high threshold but a threshold that should be achievable by any serious candidate who has a prospect of going through,” Sir Graham said.
He said it would mean a maximum of three candidates on the ballot paper for MPs to vote on.
If there are three, the candidate with the fewest number of votes after the first ballot will be eliminated. That first round is to be held between 3.30pm and 5.30pm on Monday with the result announced at 6pm.
Then, in a change in procedure since the last leadership contest, there will be an “indicative” vote once only two candidates are left.
This will be held between 6.30pm and 8.30pm on Monday, with the result announced at 9pm.
The hope is perhaps that the loser of the “indicative” vote may drop out of the race, in which case a new leader emerges without the involvement of Tory party members.
When David Cameron quit, the leadership contest did not go to a vote of party members as Theresa May was left unopposed following Andrea Leadsom’s withdrawal from the race.
If neither drops out, this final vote by MPs will allow Tory members to know – which they did not in the last election – the preferred of the two candidates of the parliamentary party, potentially dissuading them from choosing the other.
– What happens after the parliamentary stage of the contest?
If two candidates end up remaining, Tory members across the country who joined the party at least three months ago will have a say.
Tory party chairman Jake Berry said: “We have decided that if the party should decide to put forward two candidates there would be an expedited, binding, online vote of Conservative Party members to choose its next leader”.
The ballot will close at 11am on Friday, October 28, with the result announced later that day.
– Will there be any hustings?
Sir Jake Berry said Conservative HQ will be working with broadcasters to arrange one broadcast event so members can hear from the final two candidates before they vote.
– Who could run to succeed Ms Truss?
Allies of former leader Mr Johnson pushed for him to make a comeback, despite being forced out earlier this year, while Rishi Sunak, who defeated Ms Truss among MPs in the last contest but lost out among party members, also has supporters at Westminster.
Chancellor Jeremy Hunt was quick to rule himself out as he focuses on calming the financial markets, while Michael Gove will also sit out the contest.
Commons Leader Penny Mordaunt, viewed as a potential leadership contender after coming third among MPs in the last contest, said she would “keep calm and carry on”.
Other names bandied around as potential successors have included Ms Braverman, Ben Wallace, Kit Malthouse, Grant Shapps and Sajid Javid.
Defence Secretary Mr Wallace, a popular figure within the party, has insisted he wants to remain in his current job.
Ms Braverman could have support from MPs on the Tory right, but she is unlikely to prove a unifying figure.
