Former work and pensions secretary Chloe Smith has announced she will stand down as an MP at the next election.
Ms Smith, who served in Liz Truss's cabinet during her brief tenure in No 10, has held the Norwich North seat since 2009.
She has also held ministerial jobs across several departments during her time as a Tory MP, including the Treasury and Northern Ireland Office.
With a majority of just 4,738, Norwich North is seen as a top target for Labour, requiring a swing of 5.1% to take it away from the Conservatives.
In a statement announcing her intention to step back after this parliament, she said: "I have been honoured to be Norwich North's MP. It's a fantastic job for a fantastic place, and it's a particular privilege to be able to represent Norwich and Norfolk where I come from.
"I am grateful to the thousands of Norwich citizens who placed their trust in me so many times.
"I would also like to thank my team of volunteers who work so hard alongside me to help the community, and who have been so supportive, including during tough personal times.
"I hope I've been able to make a difference, locally and nationally. In 2024, after 15 years of service, it will be the right time to step back, for me and my young family."
Ms Smith first won the seat in a by-election triggered by the resignation of Labour MP Ian Gibson following the expenses scandal.
At just 27, she became Britain's youngest MP.
Analysis - by ITV News Anglia political correspondent Emma Hutchinson
Chloe Smith won Norwich North in July 2009, a by-election following the resignation of Labour's Ian Gibson during the expenses controversy.
It was a symbolic moment, with under a year to go until the 2010 General Election. David Cameron visited the constituency a record number of times during the campaign to show support. In May 2010, Chloe Smith retained the seat and Cameron became PM.
At 27, she was the Baby of the House - the youngest MP in the House of Commons - and by May 2010 she became a junior minister ahead of 2010 intake colleagues in the region such as Brandon Lewis, Liz Truss, George Freeman, Matt Hancock and Therese Coffey. She went on to reach the cabinet, serving as Work and Pensions Secretary for seven weeks during Liz Truss's premiership.
So why step back now?
Norwich North is a marginal constituency, switching between Labour and the Conservatives. Before 2009 Labour had held it since 1997 and since then Chloe Smith has won it five times. In 2017 she won with a majority of just 507 votes, which grew to 4,738 in 2019 - but for Labour it is one of their top targets in the East of England.
Current opinion polls show Labour nationally with a significant lead over the Conservatives but two years is a long time in politics.
Chloe Smith has been on the backbenches since Rishi Sunak became PM and may feel her ministerial career is over.
But Conservative HQ will be sorry to lose her: a young, ambitious Conservative MP who has decided her future is not in the House of Commons. They will perhaps be hoping others don't make the same decision.
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