Timeline: The SNP finances controversy

The Scottish National Party has faced a period of extraordinary turmoil, with a police probe into its finances leading to the arrests of senior party figures. Here are some of the key dates.

September 2014 - A referendum is held in which Scottish voters reject Scotland becoming an independent country by a margin of 55% to 45%. The SNP leader and first minister Alex Salmond decides to resign and is later replaced, uncontested, by his deputy Nicola Sturgeon.

May 2015 - The SNP secures a landslide win in a UK-wide general election, securing 56 of 59 seats in Scotland and 50% of votes cast north of the border. Scottish Labour is left with just one MP.

June 2016 - Voters across UK vote to leave the European Union by 52% to 48%, but in Scotland 62% of voters want to remain in the EU. Ms Sturgeon declares that Scotland is being taken out of the EU against its will, something she regards as "democratically unacceptable".

March 2017 - Ms Sturgeon announces plans for a second independence referendum. On the same day, the SNP launches the #ScotRef fundraising appeal for the campaign.

June 2017 - A UK-wide general election sees the SNP's share of the vote in Scotland fall from 50% to 37%. The #ScotRef crowdfunder is closed down early, having raised nearly half its £1m target.

December 2019 - The SNP make big gains in another general election, securing 45% of the vote in Scotland. Nicola Sturgeon says voters have sent a "clear message" on a second independence referendum.

A second fundraising website yes.scot helps take the indyref2 fighting fund total to nearly £667,000.

SNP membership peaks at nearly 126,000 in 2019 - about 100,000 higher than at the time of the 2014 independence referendum.

But the following year, the party's accounts reveal it has fallen back to about 104,000.

October 2020 - Pro-independence blogger Stuart Campbell, the man behind the Wings Over Scotland political website, highlights that according to the SNP's 2019 accounts it only has £97,000 in its bank account and total net assets of £272,000. The article "You've Been Robbed" invites donors who are "concerned about this state of affairs" to ask the SNP what has happened to their donations.

March 2021 - Three SNP officials - Edinburgh Lord Provost Frank Ross, Allison Graham and Cynthia Guthrie - resign from the party's finance and audit committee after being denied sight of the accounts. A statement from them is read out at an SNP NEC meeting, the party's ruling body. Ms Guthrie later joins the newly-launched Alba party led by Alex Salmond.

A video emerged last year of Nicola Sturgeon apparently telling this NEC meeting that the party's finances have never been stronger, and warning of the impact on future donations if anyone goes public with their concerns.

A few days later Police Scotland receives its first complaint, widely reported to be from pro-independence activist Sean Clerkin, about the SNP's finances. Several other complaints are subsequently said to have been submitted.

6 May 2021 - The SNP wins 64 seats in the Scottish Parliament election, one short of an outright majority. Nicola Sturgeon hails it as a "historic and extraordinary" fourth consecutive victory for her party. While the Covid pandemic is her priority, she says she still intends to hold an independence referendum once the crisis has passed.

29 May 2021 - MP Douglas Chapman resigns as SNP national treasurer, saying he has not "received the support of financial information required to carry out the fiduciary duties". He had only been in the job since the previous November, when he defeated long-serving treasurer Colin Beattie in an internal vote. SNP deputy leader John Swinney tells the BBC he does not understand why Mr Chapman quit and he has no knowledge of any police investigation.

A few days later, SNP MP Joanna Cherry also resigns her position on the NEC, citing concerns over "transparency" and Mr Beattie is reappointed as the party's treasurer.

June 2021 - SNP chief executive Peter Murrell, the husband of Nicola Sturgeon, provides a £107,000 loan the party to "assist with cashflow".

July 2021 - Police Scotland formally launches Operation Branchform, an investigation looking into the complaints about the SNP's finances.

September 2022 - The SNP's longstanding accountants Johnston Carmichael resign from their role as auditors, but the news does not emerge until seven months later.

15 February 2023 - Nicola Sturgeon unexpectedly announces she is resigning as SNP leader and first minister, saying she knows "in my head and in my heart" this is the right time to step down.

The Daily Record reports later that month that police interviewed key witnesses in the SNP, including Mr Chapman, as part of Operation Branchform just days before Ms Sturgeon stepped down.

16 March 2023 - The SNP confirms that members, who are eligible to take part in its leadership contest, has fallen to just over 72,000.

Two of the candidates had demanded to know how many members were eligible to vote but the party had refused to tell them.

Two days later Peter Murrell takes responsibility for the misleading of the media about party membership numbers and resigns from the chief executive role he has held since 1999.

The SNP's media chief, Murray Foote, had already quit after ridiculing newspaper reports - which later turned out to be true - that the party had lost 30,000 members.

27 March 2023 - Humza Yousaf wins the SNP leadership contest, beating Kate Forbes and Ash Regan in a vote of party members. The following day he is confirmed as the new first minister.

5 April 2023 - Mr Murrell is arrested at the Glasgow home he shares with Nicola Sturgeon. He is questioned under caution and later released without charge pending further investigation.

Police also search the SNP's headquarters in Edinburgh and confiscate a luxury motorhome parked in the driveway of Mr Murrell's 92-year-old mother in Fife. According to reports it has been there since early 2021 and was said to have been purchased as an election campaign bus, but never used.

18 April 2023 - SNP treasurer Colin Beattie is arrested at his home in Midlothian, and later released without charge pending further investigation. The following day he resigns his position as party treasurer.

25 April 2023 - Nicola Sturgeon tells reporters she had no idea such events were about to unfold when she announced her resignation two months earlier, and describes them as her "worst nightmare".

She also continues to insist that the police investigation played no part in her decision to stand down.

16 May 2023 - Police Scotland confirms it asked for warrants to search the home of Peter Murrell and Nicola Sturgeon while the SNP leadership contest was still under way, but had to wait two weeks for permission to go ahead, by which time the contest was over.

11 June2023 - Nicola Sturgeon is arrested and taken into custody after attending a police interview, by prior arrangement, in connection with the inquiry. She is released without charge seven hours later, pending further investigation.

18 April 2024 - Mr Murrell is re-arrested as part of the Police Scotland investigation and later charged over embezzlement of SNP funds.

23 May 2024 - Police Scotland officers working on Operation Branchform submit a report to the Crown Office and Procurator Fiscal Service.