The Ardrossan to Brodick route will remain a one-vessel service until the middle of May at the earliest.

It comes after the MV Isle of Arran, which usually serves as the second Arran ferry in the Summer, took over the overnight freight run on the Stornoway-Ullapool route after MV Loch Seaforth suffered a major technical failure.

CalMac’s Summer timetable should have started on April 29 but sailings have had to be cancelled between Ardrossan and Brodick due to the one-vessel service with only MV Caledonian Isles in operation.

However, the ferry operator is hopeful that summer sailings will return to normal by May 17 with the Ardrossan – Campbeltown service, which has been cancelled during this period, also returning in the same week.

It comes after specialist engineers working on the MV Loch Seaforth in Greenock advised that they expect her to be back in service by that date meaning MV Isle of Arran will go back to serving its traditional route.

CalMac say passenger bookings will have to be carefully managed until the MV Loch Seaforth is back in service and the full Summer timetable resumes.

Robbie Drummond, managing director of CalMac, said: “Clearly, the loss of the MV Loch Seaforth and how this has affected other services has caused a lot of disruption to customers, and we are so sorry about this.

“We are working closely with local businesses to make sure that all demand for travel is being met, and I am most grateful to them for their support, patience and understanding as we deal with this situation.

“We are confident that the MV Loch Seaforth will be back in service in a matter of weeks and the normal Summer timetable will be back up and running as planned.”

While the Ardrossan-Brodick route will remain as a one-vessel route for the time being, sailings on the Lochranza-Claonaig route have increased, doubling in capacity, offering an alternative to accessing Arran or the mainland.

Any passengers required to attend last-minute medical appointments will always be accommodated on CalMac routes.

This includes free taxi journeys to and from the ferry terminal and their NHS destination.

While the Pentalina may be an option for a longer-term hire, and this is being actively considered by CalMac and Transport Scotland, she is not immediately available while the Loch Seaforth is being repaired.

However, the vessel is only available for active service four weeks from when the required charter agreement is signed.