Scotland’s Auditor General is considering a new inquiry following growing concerns the  awarding of the ferry fiasco contract to tycoon Jim McColl's Ferguson Marine was rigged.

The Glen Sannox and as-yet-unnamed Hull 802 are due to be delivered in 2023 and early 2024 at a potential cost of nearly £350m  – over  three-and-a-half times the initial £97 million contract.

Being built at the Ferguson Marine shipyard in Port Glasgow – which is owned by the Scottish Government – the vessels have encountered numerous issues, leading to questions about the process and the procurement.

Deputy First Minister John Swinney has previously stated they were "not aware of any impropriety in the procurement process" while saying allegations will be looked into.

The Herald revealed in May that Ferguson Marine could not fulfil mandatory requirements to qualify to even contest for the contract for two lifeline ferries which remains languishing in an Inverclyde yard, over five years later with costs soaring from £97m to nearly £350m.

Evidence showed that the tycoon's shipyard firm which was favoured by the SNP government could not give a commitment to provide a mandatory builder's refund guarantee (BRG) as required and was unable to provide other crucial financial details.

The fails, which raised questions about the legality of the procurement process, were revealed in a confidential Pre-Qualification Questionnaire (PQQ) completed by Mr McColl's Ferguson Marine Engineering Ltd (FMEL) before it was ever even considered as a preferred bidder for the building of Glen Sannox and Hull 802 to serve Scotland's islands.

There have been further claims that Ferguson obtained a 424-page 'crib sheet' from a design consultant setting out CalMac's technical requirements, while other bidders had to re#ly on a more limited 125-page specification.  CMAL say this was not provided by them.

But particular focus fell on the failure of Ferguson to offer a builder’s refund guarantee, which would have protected public money once construction ran into problems - which it did.

The Herald: The 100-tonne block lift of the bow to be connected onto Hull 802, in the Ferguson Marine shipyard, in Port Glasgow, Scotland, 26 April 2022. .At Ferguson Marine (Port Glasgow), Hull 802 is fitted with its 100-tonne bow unit, which is the largest single

Mr McColl has said that he only bid for the work on Glen Sannox and Hull 802 after receiving written guidance from transport minister Derek Mackay that refund guarantees were not mandatory to win building work.

Mr Mackay told a local MSP in a letter six months before Mr McColl’s Ferguson Marine yard became preferred bidder that transport bosses saw refund guarantees as only “a preference”.

The Herald revealed that ministers offered a special incentive to ensure Mr McColl’s Ferguson got the £97m contract to ease the concerns of CMAL over the lack of the BRGs which would put them and the taxpayer at financial risk if things were wrong - which it did.

CMAL which procures ferries for the CalMac fleet said they were"effectively instructed" by ministers to award the contract to Ferguson.

The Auditor General said there were new concerns and claims relating to whether state-owned ferry owners and procurers Caledonian Maritime Assets Limited (CMAL)  followed due process”.

The Scottish Tories say the police should be called in to investigate.

In a letter to the Public Audit Committee on Friday, Auditor General Stephen Boyle said he was considering expanding previous audit work done on the ships, given the documentary.

Previously, Audit Scotland raised questions as to why a builder’s refund guarantee – which would protect the buyer – was not part of the contract with Ferguson Marine despite usually being a mandatory consideration.

If the decision was taken to re-investigate, Mr Boyle said, he would focus on “the circumstances that allowed (Ferguson Marine) to progress beyond the pre-qualification stage of the procurement, despite being unable to meet the mandatory requirements”.

Mr Boyle said he would investigate “(Ferguson Marine’s) access to restricted technical information about the vessels, and its use of this when preparing its bid for the contract”.

He said he would also look into “CMAL’s compliance with procurement rules (that apply to the Restricted Procedure) during the tender clarification and negotiation process”.

In his letter to the committee – which is undertaking an inquiry into the ships – Mr Boyle added: “There remain several unanswered questions on the procurement, including the circumstances surrounding (Ferguson Marine’s) inability to provide a refund guarantee, and I note that the committee has recently issued four separate written requests for further information.

“I will take the responses to these requests into account when deciding the scope of any audit work.”

He also said he will consider the responses from public bodies to the accusations and has had “initial discussions” with both CMAL and Transport Scotland about their “duties to investigate”, adding: “Both bodies will keep us informed about their planned actions and I will take this into account when considering the scope and timing of any audit work.”