Operation Branchform, the probe into the SNP's finances and funding, has cost Police Scotland more than £1 million, according to reports.

The Scottish Conservatives claimed the costs could have been reduced had senior figures in the party been "honest."

According to the Scottish Sun, the cash-stapped force has spent £1,084,620 on salary and overtime pay for officers plus the costs of vehicle hire.

READ MORE: Police 'check £95K car bought by Peter Murrell' in SNP cash probe

Operation Branchform launched in July 2021 after complaints that £660,000 raised by the party for a second independence referendum was spent on other things.

Former first minister and SNP leader Nicola Sturgeon, her husband the former SNP chief executive Peter Murrell, and the former SNP treasurer Colin Beattie have all been arrested and questioned as part of the probe.

They were all released without charge pending further investigation.

Officers searched and removed material from SNP HQ in Edinburgh and the former first minister’s house.

A luxury campervan, parked in the driveway of the Fife home of Mr Murrell’s elderly mother has also been seized.

Scottish Tory chairman Craig Hoy told the Scottish Sun: “This hit on Police Scotland’s budget — which is already overstretched — could have been avoided if senior SNP figures were honest about their financial affairs from the outset.”

READ MORE: Operation Branchform: Lawyers in 'cover-up' claim over lack of action

Police Scotland said it could not comment further because the probe is ongoing.

An SNP spokeswoman said: "Police Scotland is responsible for its expenditure and answers to the Scottish public."