NICOLA Sturgeon is set to face questions from a committee of MSPs investigating the procurement of two ferries, which are both late and over budget.

The Glen Sannox and as-yet-unnamed Hull 802 being built at Ferguson Marine are now due to be delivered in 2023 and early 2024, at a potential cost of around £209 million – more than double the initial £97 million contract.

In March, Audit Scotland said there had been a “multitude of failings” in the delivery of the two ferries, which are still under construction at the shipyard in Port Glasgow.

The First Minister will give evidence to Holyrood’s Public Audit Committee on Friday morning. The hearing is due to start at 10am and will be broadcast on the Scottish Parliament's website.

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Former transport minister Derek Mackay spoke to the committee in September and denied the contract was awarded to Ferguson Marine for political purposes.

A BBC documentary on the ferries aired last month, raising further questions about the procurement process.

It alleged the yard was in possession of a lengthy document of technical specifications before its bid for the contract was submitted.

Last week it emerged the Glen Sannox will initially have to run on diesel fuel when it enters service, despite being designed to also run on liquified natural gas (LNG).

This is due to a delay in the supply of a part which would enable the LNG engine to run.

Sturgeon has previously said she has “deep regret” over the delays and cost overruns, but insisted the Government was right to do everything possible to save jobs at the shipyard, which is currently in public ownership.

Ahead of the First Minister’s committee appearance, the Scottish Liberal Democrats said several key issues need to be addressed in her evidence.

Party leader Alex Cole-Hamilton said: “There is a real risk that Nicola Sturgeon’s appearance at the Public Audit Committee will only herald more filibustering and finger-pointing.

“When her disgraced former transport minister came to give evidence, he was hurried out the back door. His refusal to apologise for the catastrophe epitomised the SNP’s deluded approach to the whole sorry affair.

“That is why I am calling on the First Minister to address four key issues when she gives evidence.

“She must announce a new economic framework which can show how Government projects represent value for money.

“She must also announce a long-term investment plan in Scotland’s ferries, and outline a likely timeline for the completion of the new ships.”