THE number of train services running on Sundays are to be slashed by a third.

Scotrail chiefs said they had been forced to reduce the number of trains in the timetable on Sundays, starting this weekend.

The move is down to train drivers being unavailable due to ongoing negotiations about their pay.

Scotrail said Sunday rail services in Scotland are "partly dependent" on voluntary cover being provided by train drivers.

The firm said the number of drivers volunteering for Sunday work had "declined steeply" in recent days due to pay negotiations, resulting in a reduction of trains.

At this stage it is only Sunday services affected.

It is understood that around two-thirds of the service will run.

The train operator will run trains with extra carriages.

ScotRail will also operate bus services to enable connections with ferry services.

The final timetable will be published on Thursday but ScotRail is urging customers to take action now so that they can plan ahead for the weekend.

A dedicated webpage has been set up at www.scotrail.co.uk/sundays where all temporary timetables will be published alongside any other relevant information.

ScotRail said it had tabled an offer which would see train drivers receive a 2.5% pay rise and, in addition, a one-off £500 bonus payment for ensuring that Sunday services are covered. Added together, this amounts to a 3.7% offer for 2015-16. This offer has not been accepted yet.

Phil Verster, Managing Director of the ScotRail Alliance said: "We have inherited a business that runs a seven day railway with a system of staff rostering that covers only six days.

"Our customers want the same level of service right throughout the week, so we have to make changes and improve our railway.

"We cannot expect our train drivers to volunteer for so many Sundays when our rosters should reflect a modern, seven-day railway for Scotland."