Liz Truss's tenure as Prime Minister of the United Kingdom began on 6 September 2022 when she accepted an invitation from Queen Elizabeth II to form a government, succeeding Boris Johnson, and ended 49 days later on 25 October upon her resignation.

Truss defeated Rishi Sunak in the July–September 2022 Conservative Party leadership election on 5 September and was appointed prime minister the following day.

Following these events, together with mounting criticism and loss of confidence in her leadership, Truss announced on 20 October her intention to resign as party leader and as prime minister.

[7] During a hustings event, Truss suggested that it would be best to ignore the "attention seeker" Scottish First Minister Nicola Sturgeon before rejecting the possibility of a second independence referendum for Scotland.

[32][33] Truss attended the Accession Ceremony of Charles III the following day[34] and took an oath of allegiance to the King alongside other senior MPs.

[39][40] The initiative was forecast to cost approximately £150 billion in taxpayer funds to energy suppliers to make up the difference between what they pay for power in the wholesale markets, and the capped consumer prices.

[46] Throughout the summer and autumn of 2022, several railway strikes took place, after a ballot of National Union of Rail, Maritime and Transport Workers (RMT) members over whether they should take industrial action.

[52][53][54] The policies of Trussonomics involve extensive tax cuts in addition to reducing government regulation and repealing employment laws to attract businesses, encourage entrepreneurship, and grow the economy.

The proponents' expectations were that, kick-started by a temporary scheme of lending, tax revenue would eventually increase due to growth in the economy, relieving the need for amassing debt from the tax-cutting measures.

[57] It led to a run on sterling, a fall in gilt markets, lost confidence among global investors and criticism from the International Monetary Fund (IMF).

[57] Goldman Sachs, Bank of America and the IMF among others were sceptical that £45 billion unfunded tax cuts could lead to economic growth and pay for itself as the government hoped.

Conservative MP Mel Stride, a member of the Treasury Select Committee, wanted independent forecasts published to "provide reassurance and confidence to international markets and investors".

[69] Andrew Wishart, at Capital Economics, said the market reaction to Kwarteng's budget suggested mortgage rates of more than 6 per cent were now a "distinct possibility".

[70] On 27 September, the IMF also warned the UK government that it should re-evaluate the planned tax cuts announced in the mini-budget as they would heighten inequality and inflation in the country.

[73] In response, Truss and Kwarteng reversed the decision on the removal of the 45 pence of income tax for higher earners on 3 October following a significant backlash.

The International Monetary Fund (IMF), which acts to stabilise the global economy and sound economic warnings, took the unusual step of issuing a statement in which it openly criticised Truss's economic policies, stating that "the nature of the UK measures will likely increase inequality", and urging Truss's government to "re-evaluate" its tax measures, "especially those that benefit high income earners".

[88] In his first speech as prime minister, Rishi Sunak said of Truss: "She was not wrong to want to improve growth in this country; it is a noble aim.

[90] According to The Telegraph, as of 17 October, there were at least five Conservative MPs calling for Truss's resignation: Crispin Blunt, Andrew Bridgen, Angela Richardson, Charles Walker and Jamie Wallis.

[101] Truss pledged as part of her leadership campaign to lift the moratorium on fracking, yet some Conservative MPs had expressed concern about the change as it went against their 2019 manifesto.

[102][103] As the day progressed, 10 Downing Street became increasingly concerned about the potential size of the rebellion among Conservative MPs and informed the climate minister, Graham Stuart, that the vote would no longer be treated as a matter of confidence.

Although he subsequently relayed this to the House of Commons, the whips' office were not made aware of the change, resulting in confusion and disarray among Conservative MPs.

[111][112] Labour MP Chris Bryant made claims on Sky News saying that he saw MPs "physically manhandled through the voting lobby" naming Deputy Prime Minister Thérèse Coffey along with Jacob Rees-Mogg as those he saw in the "group".

Later that evening, the Speaker of the House Lindsay Hoyle announced that he had asked the Serjeant at Arms and other parliamentary officials to investigate the allegations made about the incident.

"[124] US President Joe Biden thanked Truss "for her partnership on a range of issues including holding Russia accountable for its war against Ukraine".

"[126] In February 2023, Truss wrote that she was not given a "realistic chance" to enact her policies, citing a "powerful economic establishment" and a lack of support from her own party.

[128] Analysts have stated that a harder economic downturn marked by a 2 per cent contraction in GDP can be expected, with Truss's successor potentially having to implement austerity measures and spending cuts in an attempt to restore market credibility.

[129] In November 2022, just days before Jeremy Hunt's autumn statement, an independent think tank, Resolution Foundation, estimated that the Truss government was responsible for £30bn of the £60bn fiscal hole that needs to be tackled.

[131] An Opinium poll held between 26 and 30 September 2022 projected a Labour lead of 15 points, predicting the Conservatives to lose 219 seats in a general election including ten cabinet ministers.

[133] Bookmakers placed Sunak first in their list of likely Conservative prime ministerial successors, followed in order by Hunt, Mordaunt, Wallace and Johnson.

[135] Their survey of Conservative Party members reported that a majority of them wanted Truss to resign, with their favoured front runners for her replacement being Boris Johnson as most popular, followed in order by Ben Wallace, Rishi Sunak, Penny Mordaunt, Kemi Badenoch, Jeremy Hunt, and Suella Braverman.