CALLS have been made for ferry operator CalMac to rethink its priority list as it emerged cancer patients are having treatment disrupted due to the latest ferry breakdowns.

It comes as CalMac's biggest vessel MV Loch Seaforth which operates to and from Stornoway on the Isle of Lewis remained out of action for a third day on Wednesday  - after suffering engine issues on Monday evening.

It also comes as Loganair island flights from Inverness are suspended due to industrial action and are not due to resume until April 24, even though the dispute has been resolved.

The Western Isles Cancer Care Initiative, which supports cancer patients has raised concerns over access to treatment after one had their first round of chemotherapy cancelled as a result.

Another patient ended up stranded at an Inverness hotel because they were not able to get home after surgery.

CalMac said it can support users in getting home by arranging trips on other routes.

"We have been taking action, we have helped everyone who is needing treatment this week to make it to their appointments," said a spokeswoman.

One ferry user group official said that there are continuing concerns for those on islands needing urgent medical attention and that CalMac's newly introduced prioritisation should change to give peace of mind to those people.

READ MORE: Faulty part delays return of CalMac ferry sidelined for four months

"Having the worry over whether you can meet important appointments at hospital just adds to any health issues that are already there.

The Herald: Calrdonian MacBrayne ferry Loch Seaforth off Gourock. Heading for dales Marine for engine repairs..

"CalMac do prioritise emergency responses but according to the prioritisation, customers with urgent medical appointments come below the likes of the carriage of fresh food and traffic carrying medical supplies and even the delivery of animal feed."

CalMac has been making use of the ferry user priority list in the wake of the issues that have led to the cancellation of vital island ferry services.

CalMac had earlier said that it was sourcing a spare part for Loch Seaforth which it hoped to have fitted on Tuesday.

READ MORE: CalMac uses user priority list as MV Loch Seaforth is sidelined

A coalition of island hauliers has previously said it was taking legal advice in a row over the use of prioritisation brought in by the Scottish Government-owned ferry operator in the midst of continuing disruption to lifeline services.

The 'disruption management traffic prioritisation framework' emerged ahead of the summer timetables coming in on March 31 and while at the time three key vessels remain out of action.

It emerged on Tuesday that while six vessels have been requiring repairs since Easter - prioritisation has been brought in on one of Scotland's busiest lifeline routes.

Services have been cancelled between Ullapool on the mainland and Stornoway as the nine-year-old MV Loch Seaforth was hit with issues with its engine control system.

The Herald: Vehicles disembarking from the CalMac ferry MV Loch Seaforth at Ullapool harbour. The MV Loch Seaforth sails between Ullapool, NW highlands and Stornoway on Lewis, Outer Hebrides...   Photograph by Colin Mearns.5th October 2018..

Users were invited to use the link between Uig on the Isle of Skye and Tarbert on the Isle of Harris. Tarbert is 36 miles away from Stornoway, while Uig is 135 miles away from Ullapool.

CalMac said the service would be prioritising freight, including food, medical supplies, animal feed and "time sensitive loads".

Any remaining space would then be offered to general traffic.

The 31-year-old MV Loch Tarbert, 32-year-old MV Loch Fyne were added to the roster of vessels needing repairs over Easter Sunday and Monday causing further headaches for the Scottish Government-owned ferry operator. They have returned to service.

Three more of CalMac's fleet MV Caledonian Isles, MV Hebridean Isles and MV Clansman have remained out of action since the summer timetable began on April 1 having spent weeks on the sidelines for repairs after problems discovered after overhauls.

Helen Sandison, who runs the Western Isles Cancer Care Initiative, said cancer patients on Lewis were facing particular anxiety because they needed to travel to Inverness for hospital treatment.

She said travel problems have been exacerbated because of the Loganair issues.

She said: "We had one service user today who was due to start chemo in Inverness.

"They were already disrupted because of the Loganair flights to Inverness have been disrupted for the past few weeks, so they were having to travel by ferry and book an overnight stay which they wouldn't have had to have done if the flights were operational.

"That chemo tomorrow has been cancelled - it's an added stress and worry for a patient who was ready to start their treatment."

She told the BBC that another patient has been recuperating at a hotel in Inverness because they were unable to return home to Lewis after surgery at Raigmore Hospital.

"This is the last place you want to be - you prefer to be at home after a major operation," Ms Sandison said.

Robbie Drummond, chief executive of CalMac, said: “We have an urgent medical appointment process where patients can travel on foot, and we will transport them to their appointments by taxi. This process continues through the current disruption and is separate to our disruption prioritisation process - people needing to get to urgent medical appointments are always given priority.

"Several customers have asked us for help in getting to urgent medical appointments during the current disruption, and we have helped every one of them via alternative ferry routes, and in most cases they have been able to travel with their vehicle. In the instance mentioned in the article we helped the patient get to the appointment after their original transport by plane had been cancelled. We understand that the appointment was cancelled after she arrived.

“Any islanders needing to make urgent medical appointments on the mainland who are not travelling by plane should ideally book through the NHS Patient Travel Service for the Western Isles, who will then make travel arrangements through the local ports.”