West coast ferry services should remain in the public sector, a new report says.

A study commissioned by ferry union RMT said CalMac had run the business in an "efficient and innovative" way.

Glasgow University economist Jeanette Findlay said the services could be put at risk if CalMac lost the contract.

Concerns have been raised over the future of the ferry service if privately-run Serco takes over from publicly-funded CalMac when the eight-year contract renews in May.

RMT union members have carried out a series of strikes on CalMac and Argyll Ferries vessels as a result.

Shetland ferry operator Serco Northlink has an "extremely troubled history" in public-sector contracts and "no significant experience in the maritime industry", while its "financial health and business model raise concerns", Ms Findlay reported.

RMT general secretary Mick Cash said: “This is a sober analysis of the economic case for keeping CalMac public which finds, resoundingly in favour of the 2016-24 contract being awarded to CalMac in order to preserve and increase the considerable economic benefits of publicly funded services, good employment and training standards already in place.

"Scottish taxpayers, ferry workers and passengers cannot afford these lifeline services being placed by the Scottish Government into the hands of Serco who would seek to drain profit from lifeline Scottish ferry services.”