The former boss of a Scottish train operator will head up a rail project linking Oxford and Cambridge.

Phil Verster has stepped down from his role as managing director of Scotrail and will now lead the East West Rail project.

Mr Verster, who starts the new role in spring, said: "Over the last two years I have worked with my team to launch the ScotRail Alliance, delivering hundreds of commitments and laying the ground for the exciting new train fleets that will start to arrive later this year.

"The opportunity to build on these same principles with the creation of a new business such as East West Rail is great for me and my family, and I wish the ScotRail Alliance team all the best for the future."

Network Rail chief executive Mark Carne said: "Phil has done a great job setting up the ScotRail Alliance and overseeing the delivery of one of the largest programmes of rail modernisation in Scotland since Victorian times.

"I am delighted that a leader of Phil's calibre will be heading up the new East West rail project, recently announced by the Secretary of State.

"We have agreed a replacement to succeed Phil and will be making an announcement shortly."

Mr Verster's departure from his £260,000-a-year post in Scotland follows a turbulent period for the company.

Scotrail has faced calls to be stripped of its £7bn franchise to run Scotland's railways after it was ordered to put an improvement plan in place when performance slipped below contracted standards last year.

Mr Verster, 53, appeared before a Holyrood committee on Wednesday and revealed Scottish Government plans to give a week's free train travel to ScotRail season ticket holders could collapse as it relies on £1.8m from a fund controlled by his firm which was earmarked for other initiatives.

The Scottish Liberal Democrats have called for transport minister Humza Yousaf to give a statement to Parliament over the resignation.

The party's transport spokesman Mike Rumbles said: "I will be raising this with the Presiding Officer on Tuesday.

"We need to know what led to these events and how he will make sure that train services improve in the future."

Scottish Labour leader Kezia Dugdale said: "It's clear the relationship between the SNP and ScotRail has broken down. One man has walked and the only man left standing is Humza Yousaf.

"He must address this ScotRail crisis and explain to passengers when they will see improvements. The clock is ticking."

Green MSP Alison Johnstone said Mr Verster's replacement must begin work immediately to "improve the current dismal situation".

A Scottish Government spokesman said: "We are grateful to Phil Verster for his hard work during a transitional time in charge of Abellio ScotRail and the ScotRail Alliance, and wish him well in his next venture.

"He has overseen many improvements and considerable investment which will ultimately lead to major benefits for passengers.

"There will be no let-up as we strive to help ScotRail and others improve the passenger experience over the coming weeks and months."