AN adviser to the biggest overhaul of UK rail services in a generation has backed the wholesale devolution of the Scottish rail network.

Tom Harris said all lines, signals, stations and other infrastructure owned by Network Rail should be transferred to a new body answerable to Transport Scotland, which in turn reports to Scottish ministers.

Mr Harris, a former Labour rail minister under Tony Blair and Gordon Brown, has previously said the management of Network Rail should be devolved. But in a speech to transport experts he went further, and said all its assets should be devolved too.

It would mean responsibility for both trains and tracks coming together under the Scottish Government, allowing for more efficient, joined up decision-making.

He said it would be “absurd” if Highways England was also responsible for motorways in Scotland, yet a single UK-wide body still owned and managed the rail lines north of the border, despite transport and Scotland’s train franchises being devolved.

The plan would require UK government approval and a Treasury write-off of at least the Scottish element of Network Rail’s £50bn debt.

Mr Harris is understood to have floated the idea to the Williams Rail Review, which he advises through a place on its expert challenge panel.

Set up in September under former British Airways boss Keith Williams, the review is the most far-reaching shake-up of rail services in the UK since privatisation almost 30 years.

When it reports this autumn, its recommendations on the structure of the industry and priorities for passengers and freight will automatically become government policy.

At present, rail in Scotland is a mix of the devolved and the reserved.

Transport Scotland oversees the train operating franchises, but rail infrastructure is owned and run by Network Rail, a UK-wide body under the UK Transport Secretary.

This split responsibility has been highlighted by the decline in ScotRail’s performance, as around half of its problems are due to faults on Network Rail, not the trains.

Mr Harris, a Glasgow MP from 2001 to 2015, said civil servants in London or at Network Rail’s Milton Keynes base should not be making crucial decisions about rail infrastructure in Scotland.

He said: “I have long been of the view that the maximum amount of devolution should be applied to the management of Network Rail in Scotland.

“This Rail Review gives us an opportunity to go even further.

“No one believes that Highways England should have ownership or responsibility for the motorway network here in Scotland: it is owned and maintained by the Scottish Government and it would be absurd to propose any alternative structure.

“We now have an opportunity to create a separate status for the railways in Scotland, with all infrastructure - the lines, the signalling and the stations - owned by an entirely separate organisation from Network Rail, just as Transport Scotland is separate from Highways England.

“This would simplify and speed up management decisions about our infrastructure, which should have no impact whatever on the broader GB industry and which, therefore, doesn’t need oversight by a GB-based body like Network Rail.”

Mr Harris told the Herald: “My views on the devolution of Network rail are well known. They have been in the public domain for some years. Naturally people will look at those comments and see that I have gone a step further. but it’s entirely up to Keith Williams and the Expert Challenge Panel whether they want to take my comments on board.”

The Scottish Government said: “The Scottish Government has made no secret of our repeated calls to the Secretary of State for Transport that Network Rail functions should be devolved to Scottish Ministers and the Scottish Parliament, and we welcome the growing support for that position. We fund Network Rail in Scotland, set its objectives, yet lack proper influence over its operations and that must change. The UK Rail Review, under the leadership of Keith Williams, will provide an opportunity to deliver real and meaningful structural change in Scotland. We want to see a system where we can consider all options for a railway that is fully aligned to the needs and aspirations of Scotland’s communities.”