If the most legitimate threat to Celtic on Wednesday would appear to be a potent Barcelona attack in the Camp Nou, there should be an awareness that trouble, too, could arrive from Uefa's headquarters in Switzerland.

Wednesday marks Celtic's last Champions League fixture of the season and their latest date with Uefa's control and disciplinary panel. A set of banners displayed before kick-off when Milan visited Glasgow last month, referencing the IRA hunger striker Bobby Sands unsurprisingly caught Uefa's eye. Despite deliberately convoluted claims to the contrary, Celtic's proud history does not include or require reference to Sands. Those familiar with the circumstances to which the banners alluded have cause to be affronted by a blatant lack of respect and understanding towards a highly sensitive historical situation.

That Milan incident itself, co-ordinated by Celtic's Green Brigade supporter group, was as pathetic as it was unnecessary. It overshadowed a gala occasion for the club. Neil Lennon, the Celtic manager, admitted his heart sank as soon as he saw the banner display. Lennon, it should be noted, understands more about political troubles in Northern Ireland than most.

Rather than offer remorse, the Green Brigade took strong umbrage with Celtic's criticism of them. "It is our opinion that the level of apathy from Celtic PLC towards the criminalisation of their supporters is unforgivable," the Green Brigade said. It was both the latest indication of youthful egos running amok and the lack of regard they have for either their own club or appropriate behaviour.

The Green Brigade has been established in a specific section of Celtic Park since 2010. Far from being a group of daft kids, they have quickly put together a formidable and well-organised movement. No display or message is put together on a whim.

Their benefit to the club three years ago was clear; to improve the atmosphere at mundane Scottish domestic matches. While that has been achieved, it has been at the cost of increased arrogance and protests regarding anything from Celtic's own board of directors to Scotland's political landscape. In short the Green Brigade has fallen into the trap of believing both their own hype and their significance in relation to a football club which has given them more grace than they were entitled to.

Previous indiscretions had included a "Fuck Uefa" banner at a Europa League tie and the setting off of fireworks in the Green Brigade section when Cliftonville faced Celtic in a Champions League qualifier in July. The Green Brigade's standard, domestic displays are dominated by the issuing of left-field messages rather than direct support for Lennon's successful team.

While Celtic made their displeasure towards the Green Brigade abundantly clear after the Milan affair, on Monday the club took more notable action. Friday night's scenes when Celtic visited Motherwell, which saw smoke bombs thrown – including one on to the pitch – and £10,000 worth of damage caused to a stand, was a spectacular own-goal by a section of the Scottish champions' support. This time the Green Brigade accepted a degree of culpability.

Ironically the Green Brigade perceives Scotland's national police force as somehow out to get them. As vandalism and pyrotechnic displays ensued on Friday, the police were notable by their absence in keeping with their supposed policy of not letting disorder escalate. That stance has failed, miserably.

Decent Celtic fans looked on in disgust at Motherwell as broken seats were held aloft like trophies. This section had been full half an hour before kick-off, with many of those who had legitimate tickets for the seats in question told to sit elsewhere by the time they arrived.

Now, it is the Green Brigade themselves who have been forced towards relocation. Celtic have informed 250 season ticket holders in their section that they can either shift to another area of the ground or be granted a refund for the rest of this season. In direct relation to Motherwell, 128 supporters have been suspended by Celtic from attending all games pending interviews with the club. Communication between the Green Brigade and the Celtic hierarchy, which had previously extended to a potential meeting between the group and Lennon, has now completely broken down.

Celtic have in the past been guilty of an angelic portrayal of their support which is not entirely borne out by reality. Yet it would also be unfair to regard Celtic fans as an overwhelmingly troublesome lot; particularly in the context both of historic disorder in Scotland and current problems in other countries.

Celtic's action on Monday was inevitable, given the damage this minority group is doing their reputation. If the Green Brigade are smart, they will accept the consequences of their actions. It would be bold, nonetheless, to bet on that outcome.