NEW details have emerged of the controversial £45m government loan to a firm owned by a billionaire adviser to Nicola Sturgeon.

The Herald has learned the first £15m tranche was given to Ferguson Marine Engineering Ltd, the last commercial shipyard on the Clyde, because it was “experiencing cash flow challenges”.

The problem was caused by cost overruns on a £97m government contract for two CalMac ferries which have been beset by delays.

Ferguson’s is part of the Clyde Blowers empire owned by Monaco-based Jim McColl, who sits on the First Minister’s Council of Economic Advisers.

Finance Secretary Derek Mackay learned of the cash flow issue in July 2017 and the loan was made last September, but he did not tell Holyrood’s finance committee until seven months later, when he sent a confidential letter referring to the trouble.

Until last week, there was no public record of the loan due to “commercial confidentiality”.

In June, Mr Mackay announced a further £30m loan to Ferguson’s to help it “diversify”. However records seen by the Herald cast doubt on whether this will ever be repaid.

The loan would not be repaid in a crisis until Ferguson’s insurance company, HCCI, was paid what it was owed first, as it is the first-ranked creditor.

Tory MSP Jamie Greene said: “The SNP have been anything but transparent. It took Derek Mackay over seven months to alert the Finance Committee about the first loan, and there are still huge question marks over the details.

“He then changed his story on what the money was for, saying that instead of diversification as first claimed, it was to plug a hole in the ferry contracts.

“This deal has been shrouded in secrecy. It’s not good enough for MSPs to go months in the dark - the SNP need to come clean and finally provide all the information surrounding these loans.”

The government said thorough due diligence was carried out by officials and external advisers before the loans were provided on fully commercial terms designed to enhance the future prospects of the business and generate a commercial rate of return.