In an 11-page letter to the Scottish Police Authority, John Scott QC, who leads the independent advisory group on the police’s use of Covid-19 powers, said the overall approach to the incidents in Glasgow were “consistent with … lawfulness, necessity and proportionality”.
He added: “Different outcomes in the different events do not undermine that conclusion.”
Celebrations by thousands of Rangers fans on May 15 erupted into violence in George Square, with at least 28 arrests and five police officers injured, at least one seriously.
The events in Kenmure Street saw hundreds of people gather in protest of a dawn raid in Pollokshields and saw the release of two men from the Border Force enforcement agency.
Both events were criticised by different sides of the political debate, with Mr Scott scathing of the “whataboutery” on show from elected representatives.
He said: “Some have compared the two events (many have mentioned earlier events as well in inevitable, albeit often incomplete, comparison) and suggested that Rangers supporters were treated differently than the Kenmure Street protestors.
“They are right, but really only at a point when public order considerations required action to prevent serious injury and damage to property. In fact, serious injury was suffered by police officers and others on May 15.
"That alone should be sufficient to distinguish the two events and explain the policing approach, despite attempts by some to indulge in ‘whataboutery’, including some politicians, who should know better.”
Mr Scott said the operational approach to both events “make sense” and had “due regard” to human rights considerations, adding the police approach “cannot and should not be determined by public support or abhorrence for a particular group or cause”.
He said: “The prioritisation of other policing considerations, in particular the physical safety of the public, over rigid enforcement of coronavirus restrictions, made sense in the circumstances facing Police Scotland on both occasions.
“While there may have been little overlap between the participants in the two events, policing decisions are not driven by popularity.”
Criticising the Home Office, Mr Scott said there seemed to be a “lack of appropriate planning and communication” from the government department that “served to exacerbate the situation”.
He said Police Scotland also failed to challenge the “misleading impression” there was a significant number of police officers present in Kenmure Street, adding that some police personnel attended the protest “alone” in vans that could accommodate “several personnel”.
The letter concludes bias played “no part” in operational decisions and criticised media portrayals of both incidents.
Mr Scott states: “Some political and media portrayal of events in Glasgow this month has used the differences in policing approaches to the different events to suggest bias on the part of police Scotland. Our work confirms us in our view that bias played no part in operational decisions.
"Public confidence and police legitimacy can nonetheless be impacted by such portrayals.”
Reacting to the letter, the Scottish Conservative’s shadow justice secretary Jamie Greene said it was critical “confusion is avoided” when it comes to mass gatherings.
He said: “The scenes we saw at George Square were absolutely disgraceful and it was particularly reprehensible to see frontline officers attacked while on duty.
“While we did not see such scenes at other recent gatherings in the city, many people were simply keen for clear and consistent messaging when it came to large crowds gathering, especially in light of the rise in Covid cases in Glasgow, with public health interests at the heart of such advice.
“Ensuring that any confusion is avoided will help to retain confidence in the public health messaging as well as helping to support our hard-working police officers who ultimately have to react and attend to such events irrespective of the cause or reason.”
A Scottish Government spokesperson said: “The conclusion reached by John Scott QC and his advisory group that the approach to policing events in Glasgow earlier this month was consistent with human rights principles – in particular lawfulness, necessity and proportionality – is a reassuring one.
“We have been explicit in recent weeks in reiterating that the restrictions are very clear – people should not be gathering in groups greater than advised in current guidance.
“People have to take personal responsibility for their actions, especially when we are at fragile state in the pandemic and easing out of the restrictions.
“Enforcement of the Covid-19 regulations on mass gatherings are an operational matter for Police Scotland.”