WORK on two ferries which are delayed and over-budget has passed a “reassuring milestone”, bosses at the shipyard carrying out the work have said.

The Ferguson Marine yard confirmed that the first emergency diesel generator has been run successfully on MV Glen Sannox – one of two dual fuel vessels being built for ferry operators CalMac at the Port Glasgow yard.

The generator is the first piece of major equipment to be run on the vessel, and all tests and systems “performed as expected” Ferguson Marine Port Glasgow (FMPG) said.

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The Scottish Government announced back in 2015 that the contract to construct the two lifeline ferries was going to the Port Glasgow yard.

But since then work on the ships has been plagued by delays, while the shipyard was nationalised.

The two vessels, the Glen Sannox and the as-yet-unnamed hull 802, were originally due to be completed in 2018, but have since been delayed until at least 2023 and costs have more than doubled from the original price tag of £97 million.

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However, David Tydeman, chief executive at FMPG, said that having successfully started the the first bit of rotating machinery on the Glen Sannox was a “very reassuring milestone”.

He said: “Our commissioning team has been doing a lot of maintenance work on all major equipment, supported by manufacturers, to prevent detrimental conditions during commissioning.”

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The Glen Sannox is currently scheduled to be delivered between March and May 2023, with the other vessel to be delivered between October and December 2023.

MSPs on Holyrood’s Public Audit Committee are investigating the delays in the project.