No club issues bans to its own supporters, especially not a sizeable and passionate group which does much to enhance the atmosphere at their games, lightly. 

So Celtic’s decision to refuse the members of the Green Brigade entry to Parkhead, starting at the cinch Premiership match against St Mirren tomorrow evening, will only have been taken after much careful deliberation. 

The Draconian action will not be well received by those who occupy the safe standing section of their Glasgow ground – or those who believe they bring greatly-needed noise and colour to match days. 

READ MORE: Celtic's Green Brigade gesture failed to observe code of decency

But the ultras, as has always been the case in the past when they have been denied access through the turnstiles, only have themselves to blame for their fate. Their behaviour has fallen some way short of what is acceptable for some time. The only surprise is it has taken so long to dish out this punishment.   

Hundreds of their fellow Celtic supporters responded to their public appeal to raise Palestinian flags at their recent matches against Hearts, Atletico Madrid and Hibernian. There is widespread sympathy with the plight of their people among the wider fanbase as the bloody conflict in the Middle East escalates. 

Unveiling banners which read  “Free Palestine” and “Victory to the Resistance” at Celtic Park on the very day that Hamas militants massacred over 1,000 innocent civilians in Israel and took hundreds more hostage earlier this month, though, was insensitive and imbecilic in the extreme.

It is not the only offence they have been guilty of this season. Far from it. They seem completely incapable of attending a game of football these days without becoming embroiled in unrest of some description. 

They reportedly broke into the ground before the Champions League group game against Lazio earlier this month and set up an unauthorised and offensive tifo which Celtic were subsequently fined by UEFA for.

READ MORE: Celtic suspend Green Brigade from attending all matches

Their conduct before the opening Group E encounter with Feyenoord in Rotterdam last month had not been any better. They put on an coordinated pyrotechnic display high up in stands of the dilapidated De Kuip before kick-off. A censure from the tournament organisers followed.

Their idiocy is not just confined to meetings with foreign opposition. Against Motherwell at Fir Park at the end of September there were reports of attempts to barge open fire exits, of fans without tickets tailgating through turnstiles, of stairwells being blocked. 

The pitch invasions which followed the visitors injury-time winner resulted in a policeman and a steward getting injured. But with obvious overcrowding it could have been worse. Much, much worse. 

Then there is Pig Watch. Photographs of police officers at their matches have been posted on the North Curve Celtic account on X (formerly Twitter) for some time in what the person or persons responsible claim is a “perfectly legal defence tactic of documenting officers perceived to be intimidating, aggravating or harassing supporters”. But some of those snapped have been publicly identified online and their personal safety compromised. 

It is appalling stuff. Celtic announced they were imposing an indefinite ban on the Green Brigade attending away matches 10 days ago. It is no great shock they have now extended that to home games. 

This is not the only time they have come down hard on the occupants of Section 111 hard. They moved them to other areas of their arena after damage totalling £10,000 was caused at Fir Park in 2013. They were locked out for two games in 2017 for illicit banners in a match against Linfield and igniting flares underneath banners at a Hearts match.

That led to the safety advisory group of Glasgow City Council – the body which issues Celtic with the certificate which it needs to open Parkhead on match days – to hold an emergency meeting and express its serious concerns to directors. There are fears once again that stands could be closed down.

The Green Brigade do an awful lot of good work for charity outside of football and unquestionably add to the spectacle of games. But they need to grow up, accept their actions have been bordering on dangerous as well as highly damaging to the reputation of the club they purport to love and think about their fellow fans for once in their lives. 

Talks between their representatives and the hierarchy are planned. If they fail to hold their hands up, apologise for their many misdemeanours and pledge to do better going forward they will be watching Celtic games on Sky Sports for the foreseeable future.