Thousands of Rangers fans descended on Ibrox and George Square in Glasgow in March 2021 to celebrate the club’s victory, but faced condemnation by politicians for breaching lockdown rules.
Around 30 people were arrested over the weekend, with some connected to assaults of officers.
Officials at Police Scotland had released 17 pages of almost wholly redacted correspondence in response to a Freedom of Information request last year after initially claiming their disclosure was not in the public interest.
In a transparency victory for The Scotsman after more than a year-long probe, the force has now been told to release the information following a ruling by the Scottish Information Commissioner.
Critics said the culture of secrecy at the Scottish Government was spreading across the rest of the public sector.
Deputy first minister John Swinney branded the scenes on March 6 and 7 last year as “shameful”, while Nicola Sturgeon also castigated fans.
The celebrations caused ructions between Police Scotland, Rangers and the Government, with the force and ministers accusing the club of not doing enough to prevent the gatherings.
Officials at Police Scotland were asked to release details of discussions it held with key stakeholders, including the SPFL, the Scottish Government and Glasgow City Council, about its policing plans ahead of the weekend.
Superintendent Stephen Dolan, who described himself as having “responsibility” for the policing operation that weekend, the company secretary and director of operations at the SPFL, Calum Beattie, and an unnamed Government official were involved in the discussions.
Refusing the request, Police Scotland initially claimed releasing the information would “compromise operational policing”.
They later claimed disclosure would stop officers being able to catch criminals by giving them a “heads-up” on the quality of its information and would substantially prejudice the ability of officials to provide opinions and advice.
This argument was flatly rejected by the Scottish Information Commissioner.
In most cases, the commissioner accepts that legally available exemptions to public bodies apply, but often rules in favour of disclosure when considering a key test known as the ‘public interest test’.
In this case, however, the commissioner said the exemptions used by Police Scotland on the substantive content simply did not apply.
He said: “He does not agree, however, that it provides enough detail about likely strategies or resources that would be deployed to enable anyone to understand or pre-empt Police Scotland’s policing of this or future matches, celebrations, protests or marches.
"While the commissioner agrees that protection of individuals and communities from crime and disorder is of the upmost importance, he is not persuaded from the withheld information or the submissions made by Police Scotland that the detail in the withheld information would allow anyone, even a determined individual, to take steps to avoid detection or increase the threat of criminal behaviour.”
Police Scotland have until September 5 to publish the information.
Opposition politicians accused the SNP of allowing an obsession with secrecy to spread across the public sector.
Scottish Labour’s business manager Neil Bibby said: “This decisive ruling suggests this information never should have been withheld.
“There is a real risk that the culture of secrecy and cover-up that the SNP have instilled in the Scottish Government is spreading.
“We need real leadership to restore openness and transparency to public life – but the SNP have shown no signs of wanting to deliver this.”
Scottish Conservative MSP Russell Findlay said: “Under the secretive and arrogant SNP Government, far too many Scottish public bodies treat Freedom of Information with contempt.
"Instead of indulging in such costly and futile evasion, they need a sharp reminder that the paying public are legally entitled to information.
“Journalists far too often face unjustifiable obstruction in response to legitimate enquiries."
A Police Scotland spokesperson said: “We have received the decision, which will be considered and responded to in due course.”