The Scottish Tories have demanded all correspondence between an SNP minister at the centre of a rail works controversy and the cabinet secretary she reported to be made public.

SNP Education Secretary Jenny Gilruth is under fire after being accused of using her position as transport minister to delay engineering works because it impacted on her constituency.

The row centres on proposed line electrification work between Edinburgh Haymarket and Dalmeny in West Lothian, which would have caused eight days of disruption from Boxing Day last year.

Ms Gilruth, who represents Mid Fife and Glenrothes as an MSP asked for the works to be postponed.

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The Tories say that officials told the Scottish Government this would lead to an extra £1 million in cost and cause disruption to 9,000 passengers a day due to the work taking place at non-holiday times.

The work has still not been carried out.

First Minister Humza Yousaf, who said she had “perfectly legitimate reasons “ to take the action but agreed to launch an investigation into a potential breach of the ministerial code by Ms Gilruth.

Scottish Conservative leader Douglas Ross accused the former transport minister of halting repair work affecting her constituency “for purely selfish, political reasons”, adding that the move was a “clear-cut sackable offence”.

Her interventions are detailed in a series of emails.

One of those messages states that Ms Gilruth would seek “feedback from Cab Sec on his views”, a reference to Michael Matheson, who was then the net zero, energy and transport secretary.

A message on October 19 last year, states that “the minister would like this to be paused until we have feedback from Cab Sec on his views”.

The email raises concerns that the work is “going to really affect Fife communities over Christmas”.

It says that the planned work “is not going to land well, particularly given the impacts of the current timetable on Fife”.

It adds: “The minister does not think rushing to get this out is the right approach and am asking for a 24 hour pause to allow Ms Gilruth to get Cab Sec and [REDACTED] views.”

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As a result, shadow transport minister Graham Simpson is calling on Mr Matheson, the current health secretary, to release details of all WhatsApp messages, emails, phone calls and meetings he had with Ms Gilruth on the issue.

He says it’s vital Mr Matheson explains what role he had in a ministerial edict that resulted in vital repair work being delayed at an estimated cost to the taxpayer of £1million.

The work, which was scheduled to be carried out last Christmas, has still not taken place.

Mr Simpson said: “It’s clear from the email chain that Jenny Gilruth sought Michael Matheson’s views on her intervention to block the repair works affecting her constituents.

“If she couldn’t see that her actions gave rise to a likely breach of the ministerial code – due to the conflict between her role as transport minister and a constituency MSP – the cabinet secretary, as her boss, should have.

“As a result, Michael Matheson has questions to answer over why he didn’t overrule Jenny Gilruth and give the go-ahead for the work to go ahead as originally scheduled.”

He added: “That’s why I have written to him today, requesting that he publish all correspondence he had with Jenny Gilruth over this matter.

“The public deserve transparency from SNP ministers over this controversy – rather than a repeat of the secrecy that has characterised the ferries scandal – so that they can see why and how this poor and costly decision was taken.”

Ms Gilruth refused to say whether she has broken the ministerial code, telling journalists she took decisions "in the best interests of the travelling public".

A Scottish Government spokesperson said: “The First Minister has been clear that any claim that a member of his ministerial team has breached any part of the Scottish Ministerial Code will be investigated following (an) established process.

“That will include looking at any exchanges not covered by the scope of the original FOI for which all material has already been issued.

“We have received a letter and will respond in due course.”