Nicola Sturgeon has dramatically announced she will quit as Scotland's First Minister after eight years.
The SNP leader will stay in post until a successor is appointed and will not back a candidate in the battle to replace her.
In an unexpected press conference, Ms Sturgeon said she had wrestled with the decision "for weeks" and insisted it was not a reaction to "short term pressures".
“I’ve believed that part of serving well would be to know almost instinctively when the time is right to make way for someone else," she said.
"In my head and in my heart I know that time is now"
In a powerful speech, she spoke of how the "brutality" of life as First Minister has taken its toll and how she had become a polarising figure after so long in power.
The first female - and longest serving - First Minister, Ms Sturgeon has been one of the most influential politicians of the past decade, leading the SNP to successive election victories.
She took over from Alex Salmond as First Minister in 2014 after the independence referendum and has battled for another vote on whether Scotland should strike out alone.
Ms Sturgeon's grip on power began to falter in recent months, with explosive rows about transgender prisoners and the Scottish Government's plan to make it easier for people to legally change their gender.
Her quest for Scottish independence appeared to have stalled as she failed to persuade successive Tory Prime Ministers to allow another referendum.
Support for independence is at 44% - just below the 45% who backed Yes in 2014 - according to a recent poll for Lord Ashcroft.
Her departure will mark a decisive moment for the independence movement - and there is no obvious successor for her crown.
Here we look at the runners and riders to replace her and the odds of their success.
Angus Robertson: 6-4
SNP veteran Angus Robertson is the bookies current favourite for the top job in Scottish politics.
He was MP for Moray from 2001 to 2017 when he lost his seat to Scottish Tory leader Douglas Ross.
Mr Robertson was also SNP Westminster leader until he lost his seat and SNP Depute Leader until 2018.
He made a political comeback in 2021 when he was elected as MSP for Edinburgh Central and currently serves as the Cabinet Secretary for the Constitution, External Affairs and Culture at Holyrood.
A former journalist, he joined the SNP when he was 15-years-old.
Kate Forbes: 5-1
Scottish Finance Secretary Kate Forbes is also in the frame for the top job.
Elected as MSP for Skye, Lochaber and Badenoch in 2016, her ascent to the top of Scottish politics has been rapid.
She became the first women to deliver a Budget at just 29-years-old after the shock resignation of Derek Mackay in 2020 when it emerged he'd sent a flurry of messages to a 16-year-old boy.
Ms Forbes garnered praise for her performance, which she carried out with only a day's notice.
The MSP, who has spoken about her Christian faith, reportedly made a pro-life statement at a prayer breakfast in 2018 and has refused to say she will back the Scottish Government's gender recognition reforms.
Humza Yousaf: 8-1
The Scottish Health Secretary is another favourite to be first minister.
An MSP since 2011 for Glasgow region and then Glasgow Pollok, Mr Yousaf became the first non-white and first Muslim Cabinet Minister for the Scottish Government.
He presided over the Scottish health system during Covid, including the country's vaccination drive.
But he has faced criticism for long waiting lists in the NHS and delays in A&E waiting times.
Keith Brown: 10-1
SNP Depute Leader Keith Brown has held a number of top jobs in the Scottish Government.
A former marine, he was elected as MSP for Ochil in 2007 and then Clackmannanshire and Dunblane, which was created in 2011.
He has been Cabinet Secretary for Justice and Veterans since 2021.
John Swinney: 12-1
Ms Sturgeon's trusted deputy has been her number two in Government since 2014 - the longest serving Deputy First Minister
He led the SNP between 2000 and 2004, and has held a string of Cabinet posts.
Mr Swinney became an MP in 1997 for North Tayside and was elected to represent the same constituency in 1999 at Holyrood.
He stepped down from his Westminster post in 2001 and switched to representing Perthshire North as an MSP in 2011.
He is currently Cabinet Secretary for Covid Recovery.
Joanna Cherry: 14-1
Edinburgh South West MP Joanna Cherry has been a vocal critic of Nicola Sturgeon in recent years.
She claimed she had been sacked from her role on the frontbench in Westminster in 2021 due to her views on transgender issues.
One of the party's most high profile MPs, the staunch Remainer played a key role in the Supreme Court case which found Boris Johnson's decision to prorogue Parliament in 2019 was unlawful.
As an MP, it would be difficult for her to stand to be SNP leader as she doesn't have a seat at Holyrood.
Anas Sarwar - 16-1
Scottish Labour leader Anas Sarwar is also in the frame to be the next First Minister in a sign that Ms Sturgeon's departure could boost Labour's fortunes.
The 39-year-old became Labour chief in Scotland in 2021 and led the party in the Holyrood elections.
He was MP for Glasgow Central but lost his seat to the SNP in the 2015 general election.
Mr Sarwar made a return to politics the next year as MSP for Glasgow region and was the party's health spokesman for several years.
* Odds from bookmaker Coral