A “slight delay” to the handover of the first of two ferries being built at Ferguson Marine for CalMac has been announced, with delivery pushed back to the middle of August.

Delivery of the Glen Sannox had already been delayed to the end of July but has now been postponed again to the week beginning August 19.

Deputy First Minister Kate Forbes said any delays are “disappointing” but delivery will take place this summer, while the Conservatives said the delays will hit the tourism economy.

Ferguson Marine’s interim chief executive officer, John Petticrew, outlined the change in a letter to Holyrood’s Net Zero, Energy and Transport Committee.

The Port Glasgow shipyard continues to have trouble with the liquefied natural gas (LNG) fuel system for the ferry after facing delays from suppliers.

Both Glen Sannox and its sister ship, Glen Rosa, are designed to run on both traditional marine gas oil and LNG.

Mr Petticrew’s letter said: “The LNG system has been well documented as the biggest challenge we were facing since our last report.

“It has proved even more difficult and has impacted the progress in other areas, namely the engine compartments.

“We still have a small portion to complete in the commissioning, but this has been moved to an alternate shift so as not to have further interference with other critical activities.

“This has resulted in a movement of the schedule causing a slight delay with delivery now being week commencing August 19 2024.

Glen Sannox sets sail on sea trials Glen Sannox sets sail on sea trials (Image: Jane Barlow/PA Wire)

“We are working with CalMac and CMAL (Caledonian Maritime Assets Limited) at the highest level to ensure there will be no further delays.”

He said this would not affect the vessel’s price, still expected to be between £145.5 million and £149.1 million.

Mr Petticrew also said work on Glen Rosa “is still not at the rate we would like to see” but costs on the vessel would be kept below £150 million.

The Glen Sannox and the Glen Rosa are now six years late and will cost around three times the original £97 million price tag.

Earlier this month, it emerged that the ship delivery director at Ferguson Marine had his secondment terminated and would return to his original employer – the Government-owned ferry procurement body CMAL.

Deputy First Minister Kate Forbes updated MSPs on the situation but refused to go into detail about what had caused the “breakdown of trust” which led to the manager’s sacking.

Scottish Conservative transport spokesman Graham Simpson said there must be accountability for the latest delay.

He said: “We’ve heard plenty about slight delays for more than six years.

“The fact is that every day is a huge cost and imposition on islanders who have been let down by the SNP Government’s abject failure over the ferries fiasco, which has cost Scottish taxpayers hundreds of millions. Yet not a single, ministerial head has rolled.

“This delay is going to seriously damage Arran’s tourist season, with horrific consequences for the island’s economy.

“And there’s not even any guarantee that these changes will meet with approval, so the delays caused by the SNP’s negligence could go on for years to come.”

Ms Forbes said: “While any further delay is disappointing, the decision to reschedule by three weeks will allow the yard to deliver the Glen Sannox this summer as well as protect other critical work.

“It is encouraging all parties are working together to ensure that the vessel enters service as quickly as possible.

“I will be visiting the yard soon and expect to have another full and frank discussion with the interim chief executive about delivering both vessels.

“I remain committed to ensuring these vessels are delivered for our island communities. The programme to deliver six vessels by 2026 remains on target.”

Duncan Mackison, CalMac’s interim chief executive, said: “We have reviewed our plans for sea trials and will be able to absorb this two-week delay into our own eight-week period for getting MV Glen Sannox ready to enter service.

“This slight delay has no impact on our plans to get the vessel into the fleet and carrying passengers as quickly as possible.

“We already have boots on the ground at the shipyard, including senior members of the crew, doing everything they can to support preparatory works for the vessel coming to CalMac. We will continue to liaise closely with all parties involved in completing the build of MV Glen Sannox.”