One of Scotland’s most senior police officers has been reinstated after a four-month suspension his supporters claim was the result of a “witch hunt” probe.

Assistant Chief Constable Bernard Higgins has been off work since November pending an investigation in to anonymous complaints he regarded as vexatious.

Mr Higgins’s absence hit Police Scotland just as it tried to cope with the long-term gardening leave of its now former chief, Phil Gormley.

The force even said his suspension was one of the reasons for the delay in a politically sensitive merger with the British Transport Police north of the border.

The controversial suspension was ended by the Scottish Police Authority after it received new information about claims made against him.

Mr solicitor, Callum Anderson, of Levy & McRae, said:”ACC Higgins is pleased to return to his duties.

“He has fully cooperated with every stage of the investigation and provided a substantial body of evidence to the authority to demonstrate that all of the anonymous unspecific allegations against him are entirely without foundation.”

Mr Higgins was suspended by the Scottish Police Authority, the main civilian watchdog for the force, pending a probe by the Police Investigations and Review Commissioner, or Pirc.

Pirc has not yet cleared Mr Higgins. The officer had been facing both criminal and misconduct complaints, the former also involving colleagues.

The allegations against Mr Higgins include claims he had covered up the theft of a bag that a police officer had taken home to carry kit and ordered a constable to take him and his wife to the airport.

Sources familiar with the case told The Herald that the assistant chief constable would be unlikely to face criminal charges and that any remaining matters should be cleared up soon.

Some officers feel that probe took too long - although three or four months is not an unusual period for an investigation.

Supporters of Mr Higgins are now questioning why Mr Higgins was suspended with the resulting disruption, including the appointment of two temporary assistant chiefs to cope with his work load. The decision was made by the SPA pending the Pirc investigation.

The Herald understands Mr Higgins suspension was lifted after Pirc that they saw no reason why his return to work, scheduled for a week on Monday, would affect their investigation. It is understood that previously Pirc had taken a different view.

Critics focused their fire on Pirc. Solicitor Aamer Anwar has been a long-standing critic. In a strongly worded statement, he claimed Pirc’s treatment of Mr Higgins had been a “disgrace”. He added: “To publicly shame such an officer and then to delay an inquiry that could have been completed in days, at best is institutional incompetence and at worst smells of a witch hunt.”

A spokesman for Pirc said: “In this case, reports will be submitted to both the COPFS, in relation to the criminal allegations and to the SPA in respect of the misconduct allegations, for their consideration of any appropriate action.

“The question of suspension is a matter for the SPA and is an entirely different process from its consideration of whether or not there is a case to answer by the senior officer.”

Niven Rennie, a former chief superintendent who supported Mr Higgins, said: “Don’t wish to say I told you so .....but I told you so. This was an embarrassment that could have been avoided....Bernie Higgins would not have been stupid enough to have placed himself in this situation.”

A Police Scotland spokesman said: “ACC Higgins’ return will bring greater resilience to the executive team of Police Scotland as we continue to focus on the delivery of day-to-day policing and serving the people of Scotland."

An SPA spokeswoman said: "The officer’s case has been subject to regular review and, at the latest meeting of the SPA’s Complaints and Conduct Committee on Thursday 8 March, it was decided that the conditions for suspension were no longer met and suspension should be lifted.

"While independent investigatory proceedings in relation to the officer have not concluded, the Committee’s decision has been informed by the views of the Police Investigations and Review Commissioner."