ScotRail workers are to stage two 24-hour strikes, including one on Christmas Eve, in a dispute over the sacking of an employee.

Members of the Rail Maritime and Transport union (RMT) will walk out on December 22 and again two days later, warning of "massive disruption" to services.

Union members on the firm's sleeper services will also strike for 24 hours from the evening of December 21 and again from the evening of December 23.

The union said the action was in support of Scott Lewis, who the RMT claimed had been dismissed for trying to help a member of the public buy the correct ticket.