AN investigation into The State Hospital at Carstairs is looking at seven allegations, including financial impropriety and bullying, as part of a probe into "corporate governance".

The review is considering claims flagged up by the NHS anti-fraud unit of inappropriate payments, favouritism and staff on the cusp of retirement working night shifts in an attempt to boost their pensions.

It has also emerged that Health Secretary Alex Neil was informed months ago about the claims in an anonymous letter by hospital staff.

The facility at Carstairs, home to many of the country's most dangerous criminals, is run by the State Hospitals Board for Scotland, which is part of the NHS.

However, the hospital has been in difficulty over reports in June that a handful of senior staff had received extra allowances totalling £50,000.

An independent probe was launched, dealing both with the payments issue and allegations of bullying by chief executive Andreana Adamson, who has stood aside while the probe is being conducted.

Following a freedom of information request, The State Hospital released the remit of the investigation on Monday.

Twenty-four hours later, hospital officials said they had sent the document in error and asked for it back.

The Sunday Herald can now reveal the "terms of reference" of the independent investigation set up by the chair of The State Hospital.

The "background" section of the document lays out a detailed chronology of the allegations behind the probe.

In November last year, the chair of the health board was informed about complaints relating to allegations of "bullying behaviour" by chief executive Andreana Adamson.

Days later, the NHS Counter Fraud Services informed the chair that some senior members of staff had allegedly received backdated payments "to which they may not be entitled".

It was alleged these allowances had not been made "in line with governance policies" and that the payments had been signed off inappropriately.

On December 21, CFS contacted the chair again about five new allegations regarding "practices" at The State Hospital.

These were: allegations of favouritism; a disputed payment issue; and nursing staff on the verge of retirement allegedly being given night shifts with the aim of "boosting pensions".

However, the terms of reference makes clear that night shifts for pre-retirees have since ceased. The other allegations were some staff wrongly being recommended for a beneficial status and individuals being appointed to unadvertised posts.

The "background" section added that, on January 18, the chair was informed that Health Secretary Alex Neil, former NHS chief executive Derek Feeley and another health specialist had received an anonymous letter repeating many of the allegations.

It was noted that the allegations had prompted three internal audits, none of which found fraud, but which dealt with issues "of great concern to the non-executive directors".

As a result of these concerns, the chair commissioned the independent investigation.

In the "objective and scope" section of the terms of reference, it was noted that the probe was to consider the "effectiveness of corporate governance" covering the period of the allegations.

It was also to look at the outcome of the internal inquiries into all the claims. The investigation was also tasked with focusing on whether the allegations suggested "broader cultural issues" in the organisation, as well as assessing relations between the board and the hospital's executive team.

Labour MSP Neil Findlay said: "Alex Neil needs to explain why it took months from receiving serious allegations about the management of The State Hospital, to him finally taking action after the press asked questions. Yet again, we have the Cabinet Secretary acting only when the headlines begin to look bad. That isn't good enough. Our health service needs and deserves leadership and direction."

A Scottish Government spokesperson said: "Following these allegations coming to light, these issues were raised by the Scottish Government with the chair of The State Hospital, who informed us that he had instructed KPMG to undertake an audit. It is the responsibility of the chair to ensure that all allegations relating to The State Hospital are fully investigated and appropriate action taken."

Stephen Milloy, the acting chief executive of The State Hospital, said: "The contents of the terms of reference are the subject of an independent investigation set up by the chair of the board. This is now well under way and as such it would not be appropriate for me to comment beyond that."