Liz Truss announced her resignation on 20 October after just 45 days in office, making her the UK's shortest ever prime minister.
Truss had faced calls to resign following the devastating fallout from her mini-budget which triggered chaos both in the UK economy and within her own party.
In a brief statement outside Downing Street, Truss said: "I recognise… given the situation I cannot deliver the mandate on which I was elected by the Conservative Party.”
Truss said that her successor would be selected within a week, with contenders including former leadership hopefuls former chancellor Rishi Sunak and leader of the House Penny Mordaunt.
There are also growing reports that Boris Johnson may be seeking to stage a comeback and run for office, despite currently being on holiday in the Caribbean.
Here are seven key dates which marked the beginning of the end of Truss' premiership.
23 September: Kwasi Kwarteng's mini-budget
In his first intervention as chancellor, Kwarteng announced a spree of tax cuts to be funded by borrowing at a cost of around £50bn.
It came after tax cuts funded by borrowing was a key promise in Truss's Tory leadership campaign.
However, the measures immediately triggered panic on the global economic markets.
The pound plummeted to its lowest ever level against the dollar, the Bank of England (BoE) was forced to buy tens of billions of UK government debt to avoid a collapse on pensions, and the International Monetary Fund (IMF) warned the UK government's policies were reckless.
Concern grew globally that the UK economy was entering an unsustainable footing, and the cost of government borrowing soared.
Amid the chaos, Truss and Kwarteng were not seen publicly for days, ostensibly avoiding facing the backlash.
2 October: Truss admits she 'should've done more' to 'lay the ground' for economic plan
Internal dissent in the Tory party grew in the aftermath of the mini-budget and market turmoil, but Truss continued to defend her economic plan, claiming it is the right plan for growth.
However, she admitted she could have done more to prepare the groundwork for Kwarteng’s financial statement after the pair blocked the Office for Budget Responsibility (OBR) from assessing their plans.
Truss also began to face accusations she had thrown her chancellor "under the bus" amid reports that claimed the abolition of the 45p top rate of tax was made by him, and not discussed with the cabinet.
3 October: Kwarteng announces U-turn on tax cut for highest earners
The 45p tax cut became so politically problematic it triggered open dissent among a number of Tory MPs and criticism from experts, after it emerged the government refused to rule out a cut in benefits to pay for it.
Kwarteng u-turned on the tax cut, saving around £2bn a year – but the move did little to calm the panicking markets with the majority of the unfunded tax cuts remaining.
10 October: Government agrees to fiscal event on Halloween to cut UK debt
After pressure to allow scrutiny on how they'll pay for their mini-budget, the government agreed to allow the OBR to assess their plans and promised to outline how they'll pay for it – indicating public spending cuts lay ahead.
Kwarteng had brought forward the reveal date of his debt-cutting plan by three weeks, in another sign of reactionary panic.
14 October: Kwasi Kwarteng sacked as chancellor
Kwarteng became the second shortest serving chancellor in UK history, having been ordered home early from a trip to the IMF in Washington, DC only to be fired.
He said he had accepted the request to “stand aside” as chancellor as Truss attempted to regain confidence in the markets by appointing former cabinet minister and senior Tory Jeremy Hunt as chancellor.
17 October: Jeremy Hunt reverses almost all of the mini-budget
Almost immediately after being appointed as chancellor, Hunt announced he would reverse almost every single one of Truss's landmark tax cuts in a bid to stabilise the British economy and restore market confidence in the UK economy.
In another damaging u-turn, he also scaled back the government's energy bills support package – which originally set the energy price cap at £2,500 for two years – to just six months.
Hunt said it will now go on for six months before being re-visited to see how it can be best targeted to both save money, while also supporting those on the lowest incomes.
The new chancellor also warned decisions of "eye-watering difficulty" are ahead on tax and spending, but pledged to protect the most vulnerable Brits.
Truss, meanwhile, gives an interview to the BBC where she apologises for the 'mistakes' made in the first weeks of her premiership.
The embattled prime minister – by now facing stinging criticism of her position – says she wanted to "accept responsibility and say sorry for the mistakes that have been made".
19 October: Home secretary Suella Braverman quits after row with PM
The new home secretary resigned citing a breach of security protocol, after sending an email related to her role from her personal email address.
However, it reportedly came after a 90 minute row over immigration policy between Truss and Braverman.
The prime minister has argued immigration is important for economic growth, but Braverman has argued it is at odds with what the British public voted for.
In her resignation letter, Braverman said she is "concerned" the government is moving away from its pledges in the 2019 manifesto, including on reducing net migration.
It also came just hours after one of Truss's special advisers was suspended pending investigation, after the press were briefed that former cabinet minister Sajid Javid was "sh*t".
Watch: Liz Truss resigns as UK prime minister