Revealed: John Swinney consulted before ferry fiasco contract was given to Jim McColl's Ferguson Marine

Ms Gilruth was accused of treating the Scottish Parliament with 'contempt' after claiming to have found a 'missing' email that showed that the ferry fiasco contract was believed to have been finally approved by Mr Mackay. But what Ms Gilruth did not say is that a series of emails reveal that Mr Swinney had a final involvement before the contract was approved.

Audit Scotland found that ministers went ahead with granting the contract in October, 2015, despite the concerns raised by the Government’s ferry procurement body, Caledonian Maritime Assets Limited (CMAL) over the lack of financial guarantees that placed them at risk.

Auditor General Stephen Boyle raised concerns about 'missing evidence' over why ministers took on the financial risk of proceeding with awarding the controversial £97m order to Ferguson Marine without mandatory refund guarantees from the shipbuilder.

READ MORE: Scots transport minister accused of parliamentary contempt as she reveals who approved ferry fiasco contract

The email was discovered at noon just before a debate on the calamitous contract which has seen two lifeline vessels still not delivered, running over five years late and over double the budget.

And Ms Gilruth at the Scottish Parliament: "I hold in my hand that irrefutable documentary evidence that this decision was made rightly and properly by the then transport minister Derek Mackay."

But further documents show that Mr Mackay's approval had been discussed with the deputy first minister John Swinney first, while there was a request to ensure there were no "banana skins" before the award was finally made.

An email on October 9, 2015 from the ferries division of the Scottish Government to Gordon Wales, the Scottish Government director of financial management and director of procurement and property Ainslie McLaughlin stated that Mr Mackay's sanction would be passed on CMAL "this afternoon" with a view to them signing a contract with [Ferguson Marine] asap.

But three minutes later, Mr Wales in an email copied to Transport Scotland asked if it "might be sensible" to wait until Mr Mackay and Mr Swinney had spoken "to ensure there are no financial/procurement issues that he might want further reassurance on".

He added: "Unless there is a critical deadline, my sense is that...we should hold fire for a few hours."

Just over an hour later, Mr Wales emailed Mr McLaughlin to ask him to drop a note in the system to "confirm the absence of banana skins after your call with DFM please (worth letting him know the intention is to tell CMAL immediately)".

It is not clear whether that "note in the system" has been disclosed.

An hour and a half later, Mr McLaughlin responded to Mr Wales saying: "Just finished my call with DFM. He now understands the background and that Mr Mckay has cleared the proposal. So the way is clear to award."

Highlands and Islands MSP Edward Mountain, the former convenor of the rural economy and connectivity committee whose inquiry branded the procurement of the two new ferries a "catastrophic failure" said: "A single set of missing documents has been found quite miraculously by Scottish Ministers. I question why these documents couldn't be unearthed in time for the inquiry and Audit Scotland's inquiry. 

"This shows how much the SNP hold the Scottish Parliament in contempt.

"Had this document been available for those investigations, then John Swinney could have been called in for evidence. 

"We need a full public inquiry to ensure SNP ministers like John Swinney cannot hide from scrutiny for the ferries scandal anymore."

Nicola Sturgeon has previously denied there was a Government "cover-up" over missing documents and said that "anybody can go on to the Scottish Government website and see the sheer quantum of paperwork and recording of decisions around this issue.”

In the years since the contract was awarded, the yard has been saved from administration by the Scottish Government, and the estimated delivery of two vessels has been pushed back by at least five years, along with an increase in costs from £97m to at least £250 million.

The Glen Sannox and the as-yet-unnamed Hull 802 are now expected to be completed between March and May 2023 and between October and December 2023 respectively.

The first ship was meant to enter service on the Arran route in the summer of 2018 but is not expected to be ready until next year at the earliest - five years late. Hull 802, destined for an Outer Hebrides route, has gone the same way.

It has been suggested that the transparency failure was a breach of the Public Finance and Accountability Act and the affair has been reported to Police Scotland.

The Herald on Sunday revealed that taxpayers lost over £80m after ministers provided a £106m special incentive to ensure that the contract could go through without the normal financial safeguards from the shipbuilder.

The deal was set up to ensure the CalMac ferries contract was given to Ferguson Marine in October, 2015, to reassure CMAL who had "severe misgivings" over the yard's inability to provide financial guarantees were not out of pocket if anything went wrong.

But in the end the taxpayer ended up out of pocket to the tune of over £80m when the Inverclyde shipyard firm went under in August, 2019 - while the costs of the two ferries at the centre of the debacle continue to escalate.

Ministers approved the £106m public money loan with special provisos to CMAL to protect them and would normally have been expected to pay off the loan over 25 years using revenue it generates from the fees they get from the lease of vessels like CalMac's ferry fleet and harbour access charges.

But the £82.5m that had been drawn down from the loan became a taxpayer loss as CMAL says it was "eliminated" after Ferguson Marine went into insolvency in August, 2019.