Ian Blackford: Why has SNP Westminster chief stepped down?
Ian Blackford is to stand down as the SNP's group leader at Westminster, after five years in which he's questioned four different prime ministers.
Who is the MP for Ross, Skye and Lochaber, and why has he left office?
Ian Blackford was born in Edinburgh and educated at the city's Royal High School.
Prior to entering parliament, he had a successful and varied career in business, including as a banker with NatWest and Deutsche Bank.
He spent time as an independent financial consultant, setting up an investor relations company, and has also worked with a telecommunications firm and a funeral planning trust.
However, he prefers to portray himself as a "simple crofter" - he farms sheep in Skye, and frequently posts pictures of them online. 
In politics, he stood unsuccessfully in the 1997 general election in Ayr, and in a by-election in Paisley South later that year - where he lost to future Scottish Secretary Douglas Alexander.
He served as the SNP's treasurer, but was removed from the post in 2000 amid a row with then-leader Alex Salmond.
Mr Blackford was eventually elected to Westminster as part of the SNP's 2015 landslide, when the party gained 50 seats.
His was a particularly controversial victory, coming at the expense of former Lib Dem leader Charles Kennedy.
It was a ferocious contest, and one that Mr Kennedy's party felt so personally that Scottish Lib Dem chief Alex Cole-Hamilton was still talking about it when Mr Blackford stepped down.
He took over as Westminster group leader following the 2017 election thanks to Angus Robertson losing his seat, and became a member of the Privy Council.
With the SNP the third party in the Commons, Mr Blackford was afforded a front-row seat in UK political theatre - particularly during the weekly session of prime minister's questions.
He sparred with four different inhabitants of Downing Street - Theresa May, Boris Johnson, Liz Truss and Rishi Sunak - with his questions often met with loud heckling from the Conservative benches.
He was also twice thrown out of the Commons after mounting vocal protests of his own - once in 2018 during a dispute about Brexit legislation, and again in 2022 after he repeated stated that Boris Johnson had "misled" the House.
Questions about Mr Blackford's leadership had bubbled away throughout 2022, as sporadic grumbles about his performance bumped up against the growing ambitions of some of his colleagues.
In March, the Politico website said he was considering his position due to a "weeks-long row" over statements he had made about pensions in an independent Scotland.
He insisted there was "nothing in it", adding that "we are getting on with the job".
However, there was a further row in June over the handling of complaints against Glasgow MP Patrick Grady, who was suspended from parliament for two days after he was found to have made a sexual advance to a teenage staffer.
Mr Blackford was recorded during a subsequent group meeting urging members to "give as much support as possible" to Mr Grady.
It was notable that one of the SNP's MPs had not only recorded this but leaked it to the media, and led to an apology from the group leader - along with a review of the party's complaints system.
And in November it was reported that Aberdeen South MP Stephen Flynn was "on manoeuvres" and had told party bosses he was set to challenge Mr Blackford for the leadership position.
He insisted he had "no intention of standing" after the story broke in The Times newspaper, and Mr Blackford initially hinted that he planned on staying on.
But he has now confirmed he will not be putting himself forward again, saying it is time for "fresh leadership".
All of this discussion has led to speculation that Mr Blackford might have been edged out, or had jumped before he was pushed.
He denies this, and Nicola Sturgeon has also insisted that "it's not a coup", saying this was "the right time" for him to pass on the baton after five years in the job.
She also pointed to the challenges of having a huge constituency scattered across the west coast and islands of Scotland, which Mr Blackford intends to continue to represent.
ming was in part forced by the date of the group's annual general meeting, where the leader is selected.
However, opposition leaders pounced on the fact the announcement has come at a point when the independence movement is in flux, with the Supreme Court ruling out a referendum without Westminster's backing and Ms Sturgeon planning instead for the next general election.
ws the party is in turmoil - although the first minister suggested only a conspiracy theorist would believe there was a link between the two.
Mr Blackford says he is standing down to focus on a new role promoting independence to the business community.
A fresh independence campaign would certainly help bind the Westminster group together - given their position neither in government or aspiring to be in power, they need something to focus their energies.
Whoever wins the job will have a position of considerable profile within UK politics, and will know they will face questions themselves about the party's strategy.