MINISTERS will defy advice from business groups, rail industry bodies and MSPs by pressing ahead with plans for a shorter ScotRail franchise, despite warnings this would make investment in new trains less likely, a leading union figure said.

Kevin Lindsay, Scottish Secretary of train drivers' union Aslef, said plans due to be announced to the Scottish Parliament next week will see ScotRail split into two, with Caledonian Sleeper services run by a separate company to the main train operator from 2014.

It follows a meeting yesterday between Infrastructure Secretary Alex Neil and union officials from the RMT, TSSA, Unite, STUC and Mr Lindsay.

Crucially, the length of the main ScotRail franchise, which covers more than 95% of train services in Scotland, will be shortened, probably to five years, once the 10-year deal with Aberdeen-based First Group expires at the end of 2014, Mr Lindsay and others who attended the meeting claimed.

Business leaders, rail industry groups and MSPs on Holyrood's Infrastructure and Capital Investment committee have warned that longer franchises are needed to secure private investment for new trains.

However, it would make it easier for ministers to implement more radical changes to the rail network if greater powers are ceded to Scotland by the time the franchise is next renewed, industry sources say.

Mr Lindsay said the length of the main ScotRail franchise was not divulged by the Cabinet Secretary but speculation is that it would be for five years. "Alex Neil said he would be splitting the ScotRail franchise into two with Caledonian Sleeper services going into a separate, long-term franchise. He indicated the main ScotRail franchise would be a short one," he said. However, A Transport Scotland spokesman said: "Aslef have jumped the gun. Final decisions on the future of rail have still to be reached.

"As part of our consultation a number of options for the future of rail were discussed with trade unions. Once final decisions have been reached ministers will set out their plans to Parliament."

Opposition politicians said the Scottish Government had put the independence referendum ahead of passengers' interests.

Labour's Elaine Murray said: "The right balance needs to be struck to allow investment in rolling stock, but also ensure the railways are meeting the needs of travellers. Too often, neither happens."

Scottish Conservative's transport spokesman Alex Johnstone said: "Our position has always been that a ScotRail franchise attractive to investors should be a single franchise and over a longer period of time."