ScotRail managing director Phil Verster has quit his role after less than two years in the job.

The railway franchise has faced criticism over its performance in recent months.

ScotRail has been performing under its expected 91.3% punctuality target.

He has left to take up the role of managing director of East West Rail, a new railway linking Oxford to Norwich and Ipswich.

Abellio, the Dutch firm who operate the ScotRail franchise contract, say his replacement has been decided and will be confirmed shortly.

Mr Verster was appointed to the role in March 2015.

He 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."

Transport minister Humza Yousaf has threatened Abellio with breaking their franchise contract and instead replacing them with a public sector operator.

The contract can be broken in 2020 with a new franchisee operating the country's railways two years later.

Mark Carne, chief executive of Network Rail 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, from South Africa, has held a number of roles in the railway industry before his appointment to ScotRail.

He previously served as the managing director of Network Rail's London North East region as well as deputy chief executive of Irish Rail.