Douglas Ross slammed an SNP “operation” to blame disgraced former government minister Derek Mackay for a ferry scandal, as crucial documents revealed John Swinney was involved in discussions on the final deal.
The Scottish Tory leader clashed with Nicola Sturgeon during First Minister’s Questions after missing paperwork over the Ferguson Marine agreement was finally found.
Mr Ross claims the deputy first minister was culpable for giving the deal the “green light” despite warnings it could face a legal challenge in court.
He added that Mr Swinney was unable to spot obvious “banana skins” in the project, which has now seen the construction of two vessels delayed for years.
But Nicola Sturgeon accused her Tory rival of “utter desperation” and claimed Mr Mackay was still ultimately responsible.
The first minister claimed Mr Swinney had merely been given sight of the deal since he was finance secretary at the time.
She claimed that her Holyrood deputy had not been copied into discussions outlining the basis of the decision.
Mr Ross said: “Honest John’s hands are all over this dodgy deal. It’s very clear officials escalated it to John Swinney waiting for his green light.
“John Swinney couldn’t find a single banana skin when they were absolutely littered around him. There were more banana skins in this project than there are at Edinburgh Zoo.
“In one section of the redacted document it warns of a risk of legal challenge for this contract.
“It states: ‘The impact of a successful legal challenge could be high. In the worst case, the contract could be declared ineffective’.
“In other words, going ahead with this contract was such a bad idea it could open up the government to even more losses than they’ve already experienced. We all knew this was a bad deal, was it also unlawful?”
He added: “Maybe the stony silence from John Swinney, which is unusual in these exchanges, is telling in itself.”
The Tory chief argued Mr Swinney should come before parliament and explained why he signed off on the final ferry deal.
He said: “If the first minister won’t tell us all of the details, let’s hear from the deputy first minister. Let’s hear why he chose to ignore expert advice.
“Let’s hear why John Swinney decided to give the green light to a deal that opens the government up to potential legal action.
“The stench of cover-up and corruption is running through this whole sorry affair.”
But Ms Sturgeon said: “It seems obvious to anybody who is looking at this, the deputy first minister did not take the decision, he wasn’t even copied into the advice which was the basis of that decision.
“He was simply briefed on the decision after it was taken, not even at his request, but on the initiative of an official.
“It is really not unusual for finance secretaries to be briefed on all sorts of decisions that involve the spending of money. It does not mean that the finance secretary has actually taken that decision.”
The Scottish Government nationalised the failing shipyard in 2019 and still maintains the two boats – being built in Port Glasgow – will be completed.
Meanwhile, Mr Mackay has previously indicated he would be willing to appear if a Holyrood inquiry is held over the scandal.