Scores of detectives in Tayside have been under investigation of various offences since January 2012 at a cost of at least £1m.
Now, with no criminal charges made or serious wrongdoing uncovered in three years, the Scottish Police Federation, which represents the officers, has questioned the conduct of the probe.
Tayside Drug Squad was first investigated under so-called Operation Teal – one of the biggest ever inquiries in to alleged police wrong-doing in Scottish history – at the beginning of 2012.
The investigation was carried out by officers from the neighbouring Grampian force but found no criminality. Some two-dozen officers were advised they needed legal support and questioned as suspects.
This criminal probe was followed by a misconduct investigation called Operation Hortum affecting even more officers – at least 60, according to sources.
This ongoing inquiry continues just as politicians and watchdogs scrutinise what many rank-and-file officers regard as overzealous regime of lengthy internal probes in to serving officers.
David Hamilton, who chairs the north area committee of the Scottish Police Federation, said: “Operation Teal concluded that there was no criminality by any of the officers involved in Tayside Drug Squad operations.
“However this three-year nightmare continues for them, and many others with a protracted internal enquiry which has so far identified only the most minor and trivial of issues.
“Despite being blocked from career development and enduring immense pressures and stresses, these officers have kept exceptional attendance, continued to deliver impressive performance and have shown immense strength of character.
“Police officers appreciate the need for proper investigations but understandably are questioning the proportionality, impact and cost of these enquiries, particularly when there is still no end in sight.”
Mr Hamilton’s remarks echo those of Chief Superintendent Niven Rennie, president of the Association of Scottish Police Superintendents.
He has already questioned the proportionality of allegations being investigated after discovering that one of his members – who has not been named – was being probed for not wearing shoes in the office.
Police Scotland – like the forces it replaced – has a policy of not commenting on internal disciplinary matters.
MSPs on Thursday discussed the general issues of complaints and internal investigations at a meeting of the justice subcommittee on policing.
They heard from Mr Rennie and Mr Hamilton’s colleague, Scottish Police Federation general secretary Calum Steele.
Several high-profile recent investigations have focused on allegations that police accessed information in breach of data protection laws. Mr Steele argued that the focus should not be on officers who access information – but on those who disclose it. “There is nothing wrong in an officer being nosy,” he said, explaining how police shared expertise on cases.
Superintendent John McKenzie said the breach of data laws was in accessing, not disclosing. Subcommittee convener Christine Grahame said she would ask the Crown to clarify.
Aamer Anwar, a solicitor who has represented police officers accused of data protection breaches, described the charge as a “sledgehammer”.
Speaking after the subcommittee hearings, he said: “Both the Lord Advocate and the Chief Constable must review the use of legislation which had led to the systematic persecution of law abiding officers.”