Ferry operator CalMac has been forced to cut passengers numbers on its MV Isle of Mull vessel to just 45 after it failed a safety check.

Problems were identified with the ship’s evacuation system during its annual overhaul.

CalMac has confirmed passenger numbers must be temporarily limited to reflect the spaces available on its lifeboats. However, difficulties in finding replacement parts for the evacuation system mean the restriction could be in place for “several months”.

The MV Isle of Mull – which can carry about 900 passengers – is due back on the Lochboisdale to Oban route on Sunday 5 January.

A spokesperson for the operator said: “During the routine inspection of the deployed system, the Original Equipment Manufacturer (OEM) identified an issue with the embarkation slide, resulting in the slide failing the inspection.

“Due to the failure, the starboard side MES system was removed for OEM inspection and, unfortunately, failed with the same issue with the glue used in the slide construction.

“The MES is inspected during overhauls and the annual inspection completed the previous year (2023) had not identified this as a potential issue.”

They added: “Working with the OEM and after an extensive worldwide search, it has become evident that there is no like-for-like replacement available. Obsolescence combined with the design changes in the replacement systems mean that we do not have a compatible evacuation slide to embark passengers onto the life rafts in an emergency.

“It is possible that this could take several months to complete. Time will then be required to install and test the system before returning the vessel to a normal Passengers On Board figure.”

CalMac says passenger bookings on the Lochboisdale route very rarely exceed 45 passengers per sailing at this time of year.

At the time the restrictions were brought in, there were no bookings exceeding the 45 passengers per sailing limit.

The issues are the latest in a series of technical problems to hit CalMac’s ageing ferry fleet.

In October, the operator was forced into making temporary changes to some of its services due to ongoing disruption caused by repairs to the MV Caledonian Isles.

It had been due to return to its Arran route on 23 September after eight months of maintenance work, but will not now return until March.

Projects to build new ferries have also been hit by delays.

They include Glen Sannox and Glen Rosa which were originally due for delivery in 2018 but have faced repeated design and construction challenges.

It was announced earlier this month that the Glen Sannox will begin timetabled sailings on 13 January.

CalMac confirmed the vessel will enter official passenger service on the Arran route after successful tests and crew familiarisation over the past month.

Glen Sannox will run on the busiest route on the CalMac network, operating between Troon to Brodick.