AN AUDIT Scotland report published prior to a decision by transport chiefs to keep heavily criticised boats on the Gourock-Dunoon route has been slammed as a public failure.

The scrutiny body quoted figures of up to £30 million per vessel to replace the foot passenger-only craft currently operating on the crossing.

But Caledonian Maritime Assets Ltd (CMAL) — which controls Scotland's publicly-owned ferry fleet — has estimated that the cost of providing vehicle-carrying ships would be a fraction of that.

In an email sent to Labour MSP Rhoda Grant, CMAL chief executive Kevin Hobbs said that more robust 40-metre long car ferries would come in at around £10 million each.

Campaigners fighting to replace the foot passenger service have seized on the revelation and called on Auditor General Caroline Gardner to retract Audit Scotland's 'value for money advice'.

In a strongly worded letter to Ms Gardner, Susanna Rice, convenor of the Dunoon-Gourock Ferry Action Group, says: "I am concerned that the integrity of Audit Scotland may have been compromised."

The report, 'Transport Scotland's Ferry Services', uses a figure of £25m-£30m per vessel which was given to a parliamentary committee by former Caledonian MacBrayne boss Martin Dorchester in January 2017.

However, a £50,000 study by transportation consultants MVA which was commissioned by the Scottish Government concluded in June 2013 that car ferries for the route would cost around £6m each.

In her letter to the Auditor General, Mrs Rice states that the 'direct outcome' of the Audit Scotland report 'has been the cancellation of the Gourock-Dunoon tender for new 40-metre plus size vessels as a consequence of your concern at 'value for money'.

Mrs Rice adds: "We expect Audit Scotland to scrutinise Scotland's public services, ensure value for money and speak truth to power when it finds incorrect or over costly practice.

"In this your organisation has failed."

She branded Mr Dorchester's figures a 'guesstimate' which had 'no evidence' to support them.

Mrs Rice noted that the advisory group used by Audit Scotland included the head of Transport Scotland's ferry unit, adding: "In democratic states, audit methodology does not normally permit representatives of the body being investigated to also be its advisors."

A Transport Scotland spokesperson said: "We are committed to delivering a passenger ferry service between Gourock and Dunoon with improved reliability and resilience, and the minister [Paul Wheelhouse] has heard directly of local stakeholders' concerns around the suitability and resilience of the current vessels operating on the route.

"As the minister has stated to passenger representatives, the decision on new vessels for the ferry service will follow further discussion with local stakeholders on the vessels' design, but would be, broadly, based around costs identified within the MVA Report, as we share the concerns of others over the accuracy of cost data assumed in Audit Scotland's own report — something we raised directly with Audit Scotland at the time their report was published."

However, it appears that nothing has been done to replace the weather prone MV Ali Cat and MV Argyll Flyer which now operate under the CalMac banner.

A CMAL said in a statement: "CMAL has not been asked to look at passenger only replacement vessel(s) for this route at this time."

Their spokesperson said: "We responded to a request to provide an estimate cost for a 40-car, 220-passenger ferry. While we provided an estimate cost of £10m for one vessel, we advised that we have not looked into any detail around the cost of any vessels so the figure provided is a ballpark number.

"It is vital to recognise that figures are estimates and cannot be confirmed or used as final costs unless and until a full design specification has been conducted.

A spokeswoman for Audit Scotland said: "Our 2017 report on Transport Scotland's ferry services quotes the two sets of figures that were available at the time.

"The estimated figure of between £25 million and £30 million per vessel was provided by the then-chief executive of David MacBrayne to the Rural Economy and Connectivity Committee on 25 January 2017.

"This was not Audit Scotland’s assessment of the cost."