FERRY operator CalMac has warned travellers of a "inevitable" disruption after announcing that one of its largest vessels will remain out of action until “at least” mid-November.

The MV Caledonian Isles, which usually serves the Ardrossan-Brodick route, will have been out of service for the majority of the year, after first going in for repairs in January. CalMac said the work involved removing all four of the ferry’s engines.

The ferry operator said the delayed repair work meant they had been forced to extend their temporary deployment plan until the end of the summer timetable period on October 20.

The continued absence of the MV Caledonian Isles, which is one of the largest in the fleet, has coincided with the start of this year’s annual maintenance schedule for all the ferry operator’s vessels, which CalMac said has caused further problems.

READ MORE: CalMac confirms the ferries 'most likely' for disposal as new ships come in

Duncan Mackison, the operator’s interim chief executive officer, warned: “We did anticipate a difficult winter, with our major vessels spending a record number of days in annual maintenance, and it is shaping up to be just that.

“The combination of MV Caledonian Isles ongoing technical issues and the start of this year’s maintenance window has created a perfect storm for ferry services.”

Mackison warned that CalMac will likely “have to regularly review where vessels are deployed to try and maintain services across the whole west coast”.

He went on: “Our priority is to keep communities on the network informed of our plans, and meet service demands wherever we can. However, it is in inevitable there will be some disruption and on behalf of CalMac I apologise for that.

“I know this will be disappointing news for local people and many of my colleagues, who live and work in these communities, share in that disappointment.

“We are doing everything in our gift to provide certainty to people who rely on us to travel, and to add resilience to services wherever possible.”

CalMac said it will provide an update on future deployment plans by Thursday, October 17.