Caledonian MacBrayne ferry crews are to be balloted on strike action tomorrow amid fears over the future of staff pension and workplace rights.

The RMT confirmed the move as CalMac's bundle of 24 routes will go out to tender later this year, with the new contract beginning in October next year.

It fears that if the routes – most of which have been operated by the public sector for over 60 years – are broken up it could lead to private companies imposing different conditions of service.

General secretary Bob Crow, who will meet Transport Minister Keith Brown next month, said "RMT is urging all members use their vote and return a 'yes' vote for strike action over this issue."