JUSTICE Secretary Michael Matheson is facing calls to resign after one of his top officials apparently tried to interfere in the work of an independent police watchdog.

Kate Frame, the Police Investigations and Review Commissioner (Pirc), rebuffed the attempt last month, telling Mr Matheson’s aide she was “more than a little surprised” at his action.

“My perception of your remarks is of governmental interference with my independence,” she told Donald McGillvray, the Scottish Government’s deputy director of policing, after he urged her to delay the publication of a highly critical report.

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The Government insisted no interference took place, as the report came out on schedule.

However opposition MSPs said the attempt to influence the Pirc was grave enough for an inquiry into the “endemic” problem of government over-reach and for Mr Matheson to quit.

Mr Matheson is already facing claims he “unlawfully” tried to sway the Scottish Police Authority (SPA) late last year after it decided to allow absentee Chief Constable Phil Gormley to return from special leave despite the Pirc investigating bullying allegations against him.

According to the SPA’s then chair, Mr Matheson told him that was a “bad decision” on its face, then changed tack, saying his gripe was actually with the decision making process.

The dispute between Mr McGillvray and Ms Frame is documented in an email exchange, published by the Sunday Post, about a Pirc inquiry into SPA complaint handling.

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It found the way the SPA, the oversight body for Police Scotland, handled complaint about senior officers lacked clarity and transparency and was “neither effective nor efficient”.

On 30 November, Mr McGillvray wrote to Ms Frame warning the report might be seized on by Mr Gormley’s “very active” lawyers and “risk” the probe into his conduct.

Three weeks previously, the SPA had agreed to reinstate Mr Gormley, then reversed its decision after Mr Matheson urged them to “reconsider”.

Mr McGillvray suggested Mr Frame might influence the SPA informally in the meantime, using its “open door to improvement” rather than publishing her report.

“That route might carry less risk until the [Chief Constable] issue has moved on a bit, especially if the content of the report crosses over with points his lawyers are raising.”

Mr Frame replied on December 5, saying she was sticking to her original timetable.

She made her “governmental interference” remark in a further December 23 email, and the report was published on December 29.

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Tory MSP Liam Kerr said: “These new revelations show that the SNP Government’s meddling in police matters is endemic, both at the SPA and now with the PIRC.

“Michael Matheson's department has torn up the rule book that is supposed to protect the independence of our police service, and as such the Scottish public can no longer have confidence in him. Simply put, the best course of action would be for him to resign.”

Labour justice spokesman Daniel Johnson said Mr Matheson must come to parliament this week to explain the actions, and if could not do so satisfactorily, he should resign.

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He said: “This is a shocking revelation of attempted government interference in a supposedly independent investigation into the SPA, which in turn is supposed to be independent of ministers. The independence of policing is a fundamental point of principle and of law.

“Michael Matheson’s department has treated operational independence of policing with contempt with its repeated interventions.

“As Cabinet Secretary for Justice, he must take responsibility for his  actions and those of his department.

It is hard to conceive how Mr Matheson can justify these actions, but Labour will be demanding he comes to Parliament and attempts to, and if he cannot, he must resign."

Scottish LibDem leader Willie Rennie MSP said the problems in Police Scotland stemmde from an unhealthy concentration of power around the Justice Secretary.

He said: “We need an independent review of how the policing structures are operating.

“Powers over policing should be shared across more individuals and communities to avoid these situations. The revelation of further government interference in policing make the case for fresh police reform even stronger.”

A spokeswoman for the Pirc said: "During the second half of 2017, the Pirc audited and examined the SPA's complaint handling procedures for the period between 1 April 2015 to 31 March 2017.

"The Pirc was committed to publishing her independent audit report by the end of 2017 and adhered to this schedule.

"This independence was emphasised to the Scottish Government in an email on 23 December 2017.

"The comment by the commissioner in the e-mail was made to allay any potential for perception that the Government were attempting to interfere in her position of independence.

"There have been no incidents of government interference and the release of the audit document went ahead within the planned timescale."

The Scottish Government said there was no involvement from ministers in the exchange, andthe report did not overlap the period relating to complaints against Mr Gormley.

A spokesman said: “Pirc is an independent body and has made clear that there has been no interference in the publication of this report.

"The Scottish Government has no role in either the timing or content of its reports.

"It is part of the normal role of the sponsorship function to support public bodies to consider their role in the wider context of public services."