Transport Minister Humza Yousaf has repeated his calls for control over Network Rail to be devolved to Scotland following a report criticising its handling of major infrastructure projects north of the border.

Mr Yousaf said the EY review of rail projects has "exposed fundamental weaknesses" in the organisation's project governance, controls and performance reporting, as well as "weak and inconsistent" cost forecasting.

Network Rail was reclassified as an arm's-length UK Government body in 2014.

The EY review, commissioned by Transport Scotland, looked at projects including improvement works to the Aberdeen to Inverness line and the Highland Mainline, and the Edinburgh to Glasgow Improvement Programme, among others.

It found that Network Rail's cost estimating can be unreliable, and there is an inconsistent approach to cost reporting.

Other issues highlighted in the report include a lack of dedicated project control system, while project schedules were found to be "lacking in robustness".

The quality of performance reporting was also found to be poor and in some cases lacking in transparency.

Mr Yousaf said: "The Scottish Government has warned repeatedly that there needs to be fundamental changes in how our railways are run.

"Time and time again we have set out a full and compelling case to the UK Government for the full devolution of Network Rail to Scotland.

"Time and time again these requests have been rejected, most recently in March this year, yet this review adds weight to our calls for transformation.

"We know passengers are already frustrated, not least as this review comes hot on the heels of the need for ScotRail to implement a Performance Improvement Plan - something we are closely monitoring. While we are doing what we can to address the issues at hand, our powers are limited.

"That is why I have made clear to Network Rail's chair Sir Peter Hendy and chief executive Mark Carne my expectation that they will increase the scale and pace of their decentralisation agenda.

"As a minimum I expect this to include the full transfer of responsibilities for the development, design and delivery of infrastructure projects to their Scotland route."