Fergusons, the last yard in Scotland still handling non-defence orders, was nationalised by Holyrood ministers late last year after a contract to build two new ferries was beset by massive delays and cost overruns.
Jim McColl, the Monaco-based billionaire who took charge of the shipyard in 2014 through his Clyde Blowers company, has been critical of how the Scottish Government has handled the debacle.
A dossier, compiled by a QC on McColl's behalf, has now claimed Nicola Sturgeon's failure to mediate between Fergusons bosses and government quango Caledonian Maritime Assets Ltd (CMAL) led to the yard's collapse and left taxpayers picking up the bill.
The document suggests ministers were wrong to reject a shared ownership rescue plan on legal grounds. It said a proposal by Mr McColl to split additional costs 50-50 with the Scottish Government could have saved taxpayers £120m.
Mr McColl appeared before a Holyrood committee earlier this month and called for a public inquiry into the fiasco.
A Scottish Government spokeswoman said ministers would soon be providing a detailed response to Mr McColl’s committee evidence, which included a number of points it did not recognise.
“As we have stated having considered CBC’s alternative proposal over a number of weeks Minister found it unviable, raising significant risks, requiring significant investment from Ministers and withdrawing the remaining investment already committed by CBC. CBC’s proposal offered no further investments in the business from them.
“We have worked for more than two years to find a resolution to the difficulties at Ferguson Marine and with the completion of the two CalMac ferries, protecting jobs, and securing a future for the yard as our priorities and that remains our priority.
“Three staff have left by mutual agreement but no staff have been dismissed and in fact the workforce at Ferguson Marine has increased by nearly 50 people, since it entered public ownership.”