Police Scotland has asked an external force to conduct a review following claims of “unprofessional” conduct within the now-defunct Scottish Crime and Drug Enforcement Agency (SCDEA).

Chief Constable Iain Livingstone said the independent peer review, which follows a recent internal review, would be carried out by a force with “significant” experience in covert policing.

The details are contained in a paper presented by the Chief Constable ahead of Wednesday’s meeting of the Scottish Police Authority board.

The move follows a recent civil action involving a former Grampian Police officer who was seconded to the former SCDEA.

The court case centred around how the former officer was treated following the discovery of mismanagement at the SCDEA’s Special Operations Unit (SOU) in April 2011.

The paper says: “During the former officer’s evidence, a number of assertions were made regarding unprofessional practice, including that documents were destroyed by burning following the April 2011 discovery.”

Mr Livingstone said there was legitimate interest in what had taken place at the SCDEA and he instructed Police Scotland’s Anti-Corruption Unit to review the chronology, previous investigations and steps taken. That review is now complete.

Announcing the next steps, the Chief Constable said in the paper: “It is clear that the events which took place in the legacy SCDEA in 2011, as described in the civil action, were wholly unsatisfactory and unprofessional.

“I have now considered Police Scotland review team’s conclusions and recommendations.

“While I am entirely satisfied that the review was a thorough, robust and appropriate response, I recognise the legitimate interest that exists about what took place in 2011, and the importance of public confidence in the vital area of covert policing.

“To that end, I have requested that an external force, which has significant knowledge and experience in the area of covert policing, carry out a peer review to provide independent assurance.

“The purpose of this independent peer review is to ensure all legitimate inquiries have been carried out, and to identify whether there are any further lines of investigation which should be pursued.

“On completion and receipt of the peer review, I will determine what steps, if any, are required to ensure the integrity of the Police Scotland response and provide further public reassurance over this episode.”

The SCDEA, along with Scotland’s eight police forces, merged to form Police Scotland in April 2013.