The ongoing investigation into the SNP's finances has now officially passed to Sir Iain Livingstone's deputy designate following the chief constable's retirement today.

Sir Iain finished his final working day at Police Scotland this afternoon with deputy chief constable designate Fiona Taylor now in charge of the high profile inquiry - and all other operations and matters relating to the force.

There had been speculation that Operation Branchform may be completed by the time Sir Iain stood down this afternoon after he said last month "the sooner the probe into SNP finances is completed the better for everyone involved".

He insisted the two-year long investigation was “entirely legitimate” and denied it had been politically motivated.

"We are duty bound to investigate matters if they are reported to us," he told the BBC at the time.

"Our action and our investigation is in the interests of everybody involved because it will clarify facts and deal with evidence and facts as opposed to rumour and innuendo. So the sooner this investigation is concluded, the better for everyone involved."

He did not put a timescale on the investigation concluding.

"It has to take its course. We will continue to work very closely with independent prosecutors and matters will progress in due course," he added.

Sir Iain had previously defended the scale of the investigation as "prudent, thorough and proportionate” as well as the erection of a blue police evidence tent outside Ms Sturgeon’s house.

He revealed in a separate interview last month that the investigation into the SNP’s finances had grown beyond the initial allegation of fraud.

He hinted Operation Branchform had expanded to look at “potential embezzlement” and the “misuse of funds” since being launched two years ago.

“It's moved beyond what some of the initial reports were, and that's not uncommon in investigations such as this," he said.

In July 2021 the police confirmed they were investigating complaints made around donations to the SNP.

It followed allegations that £600,000 raised for campaigning towards Scottish independence was diverted elsewhere.

In the past several months, three figures in the party have been arrested in connection with the allegations: former leader Nicola Sturgeon; her husband, the former chief executive, Peter Murrell; and MSP Colin Beattie, who stood down as treasurer.

All were released without charge pending further inquiries. When she returned to Holyrood in June, Ms Sturgeon said she was certain she had done nothing wrong.

Police Scotland today confirmed that so far no one has been charged in the investigation.

A spokesman added: “As the investigation is ongoing we are unable to comment further.”

The Crown Office and Procurator Fiscal Service said it had not received a report from police on the investigation.

Police Scotland’s next chief constable Jo Farrell will take up her post on 9 October. She will be the force's first woman chief constable.

Sir Iain, Ms Farrell and Ms Taylor met with Justice Secretary Angela Constance and Scottish Police Authority Chair Martyn Evans at Police Scotland Headquarters, Tulliallan on August 1 to finalise the leadership transition arrangements.

Sir Iain said: “An effective handover which maintains stability in Police Scotland was a key priority in my retirement plans and I will continue to work with Fiona and Jo to that end.”

DCC Designate Taylor said: “My focus will be on ensuring effective policing is maintained for the communities of Scotland and I will support the effective handover from Sir Iain to Chief Constable Farrell.”

Chief Constable Farrell said: “I thank Sir Iain and Fiona for their work to ensure a smooth transition when I take command of Police Scotland.”

The leadership arrangements were agreed by the Scottish Police Authority.

Justice Secretary Angela Constance said after the meeting: “I’m pleased to meet Jo Farrell ahead of her taking up post as Chief Constable and looking forward to working with her in the years to come.”