Ministers have come under new fire over secrecy relating to the delivery of vessels at the centre of Scotland's ferry fiasco - after repeatedly refusing to explain its rationale for ploughing millions more into their delivery.

The Scottish Government has repeatedly blocked calls to divulge details of reports on the rationale for going ahead with one of two stricken ferries when it was considered not value for money.

It has also blocked any publication of any part of a secret report into how the nationalised shipyard firm is punctuating ministers' decision-making over nationalised shipyard firm Ferguson Marine (Port Glasgow).

Wellbeing Economy, Fair Work and Energy Secretary Neil Gray admitted in May that the value for money case for delivery of Glen Rosa "had not been made" and that it would be cheaper to procure a new ferry, saying increasing costs were "extremely disappointing".

READ MORE: Ministers do not rule out more public money millions over ferry crisis

He gave a rare written authority to plough ahead with supporting the delivery of the two ferries at Ferguson Marine, saying it is the "platform upon which future success can be built".

He said that non-delivery of the ferries at nationalised Inverclyde shipyard firm Ferguson Marine (Port Glasgow) would put the very future of the yard and the jobs it supports "in jeopardy".

And he said procuring a new vessel would mean it would not be delivered till May 2027 at the earliest and said that the value for money case for the second delayed vessel Glen Sannox had been met.

It marked the sanctioning of an extra £72m cash requested by nationalised shipyard firm Ferguson Marine which had been under due diligence since September last year. That was because of continuing concerns about the soaring costs of the two lifeline ferries that are now around six years late – with costs expected to be quadruple the original £97m contract.

The Herald: Ferguson Marine

But the Scottish Government is steadfastly refusing to explain the financial evaluation that lay behind the decision to reject the value for money case and plough ahead.

It has refused to say what the costing assumptions that were made for starting the vessel from scratch against the real extra costs of completing the ferry.

The 'value for money' analysis by consultants Teneo – that cost the taxpayer £620,000 – will not be disclosed because it is feared it will jeopardise the future of Ferguson Marine.

The review said it would be cheaper to scrap Hull 802 and place a new order elsewhere. But the government said continuing to build Glen Rosa was the fastest way of securing a new ship.

Attempts to get a detailed comparison of the cost of completing Glen Rosa against the cost of scrapping it and starting again through Freedom of Information legislation have also failed.

But the convener of the Scottish Parliament's public audit committee Richard Leonard has said details of the financial reasoning for forging ahead must be made available.

He says a separate report by consultants First Marine International (FMI) that was also considered as part of wider work to evaluate the shipyard’s productivity and looked at improvements needed to make the shipyard firm financially viable should also be made available.

He has told Mr Gray: "The committee is disappointed that despite repeated requests, the Scottish Government is unwilling to publish any information from the two commissioned reports on the funding and future options for FMPG and the due diligence used to make a value for money assessment on the completion of vessel 802 at FMPG.

"In its report, New Vessels for the Clyde and Hebrides: Arrangements to Deliver Vessels 801 and 802  the committee was clear that it wants to see a positive future for the shipyard.

"It therefore does not seek to jeopardise the sustainability or future successes of FMPG. Indeed, in our correspondence to you on this matter, we accepted that some commercially sensitive information in the reports may not be able to be published.

The Herald:

Publication of a Scottish Government analysis relating to  ferries  due diligence and value for money was almost totally wiped out through redactions.

"The committee believes that a balance can be struck between recognising issues of commercial confidentiality and the ability of parliament to hold the Scottish Government to account regarding the information that it has used to make critical decisions about the yard and the vessels.

"The committee therefore invites you to consider once again your position on this matter and explore whether any information from these reports can be made publicly available."

The Scottish Government has previously come under fire for ferry secrecy by refusing to publish the full details of the full contract between Ferguson Marine and government-owned ferry owning and procurement agency Caledonian Maritime Assets Ltd (CMAL) into the building of the stricken vessels.

Tycoon Jim McColl, the former owner of Ferguson Marine – before it went into administration in August 2019 and nationalised by the Scottish Government – said it showed it was not a fixed price contract and he was entitled to ask for extra money to fulfil it.

Vital pages were removed from the document before they were finally published by the Scottish Government. These include crucial financial details about the contract, guarantees, payment details, permissible delays and cost liabilities.

The full contract was finally published by the Scottish Government in July, after Mr McColl submitted it to the public audit committee.

A Scottish Government spokesman said:“The Scottish Government remains committed to being as open and transparent as possible in relation to decisions around Ferguson Marine (FMPG) and vessels [Glen Sannox and  Glen Rosa].

“As previously set out, the disclosure of due diligence reports would impact on FMPG’s ability to compete for and win new business, jeopardising the commercial future of the shipyard.

The Herald: Glen Sannox

“The due diligence concluded that the value for money criteria were met for Glen Sannox. In setting out the decision to issue a written authority to enable work on vessel 802 [Glen Rosa] to continue, there was clear, cross-party acknowledgement that this was the appropriate course of action – not least as it presented the fastest possible route to getting vital new lifeline services into service.

“We have received correspondence from the committee convener and will reply in due course.”