Former chancellor Kwasi Kwarteng will stand down at the next election.
Mr Kwarteng delivered the disastrous mini-budget, and was later sacked by then prime minister Liz Truss and replaced with Jeremy Hunt in a bid to reassure markets.
The Truss administration collapsed shortly after.
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Mr Kwarteng is the MP for Spelthorne in Surrey, and holds it with a majority of 18,393.
Writing on social media, Mr Kwarteng said: “Yesterday I informed my association chair of my decision not to stand at the next general election.
“It has been an honour to serve the residents of Spelthorne since 2010, and I shall continue to do so for the remainder of my time in parliament.”
According to a Sky News tally, he is the 55th Conservative MP to say he will not stand at the next election.
The announcement came shortly before Ms Truss launched her new “Popular Conservatives” movement.
Mr Kwarteng has worked for various Conservative governments since 2015, including as a Brexit minister, a business minister, before being promoted to the cabinet as business secretary by Boris Johnson in January 2021.
A close ally of Ms Truss, he was a vocal supporter of her campaign to become leader of the Tory Party and the country, and she appointed him chancellor on 6 September 2022.
He was sacked on 14 October 2022 – 38 days later.
Read more: What was in the mini-budget and what was scrapped
On 23 September 2022, Mr Kwarteng delivered the mini-budget – the economic plan promised by Ms Truss which her supporters claimed would grow the economy.
It followed the announcement of a plan to cap energy prices for a typical household to £2,500 amid surging costs.
What followed was market and political chaos, worries that pension firms would collapse, and ultimately the defenestration of the UK’s second shortest-lasting chancellor. Only Iain MacLeod, who died 30 days after taking the role in 1970, has spent less time in charge of the country’s finances.
Eventually, the Bank of England intervened to prop up markets.
The energy cap – which has since been estimated to have cost £21bn – and the mini-budget did not have the impact the Truss team thought they would. She had promised “supply-side reform” that would boost growth in her campaigns.
Rishi Sunak, who lost in a vote with Tory members to Ms Truss, repeatedly criticised her plans as not being financially sound.
One issue that spooked the markets was the lack of an official forecast for the mini-budget – usually carried out by the Office for Budget Responsibility (OBR).
This, alongside measures like the scrapping of the top rate of income tax and holding corporation tax at 19%, led to uncertainty about the UK economy and how money would be raised in the future.
Mr Kwarteng was forced to U-turn on the income tax pledged in the middle of that year’s Conservative Party conference.
He then attended an International Monetary Fund summit in the US – before cutting the trip short to return to the UK.
As he was travelling to Downing Street, Mr Kwarteng learned he was being sacked on social media from a post by a journalist.
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Oct 2022: Kwarteng U-turns on income tax
Ms Truss later confirmed another U-turn, saying corporation tax would rise as originally planned to 25%.
Since these events, Mr Kwarteng has admitted that not involving the OBR in his planning was “probably a mistake”.
