All through the “troubles” fireworks were banned in Northern Ireland. Displays could only be held by those with a license.
For a long time, most people adhered to the ban. However, after a time it became easier to acquire them and they were quite often used at times of civil unrest, by rioters, alongside petrol bombs and illegal firearms.
With the Good Friday Agreement and all that, they are widely available and their sole purpose seems to be to torture poor pets for about 3 weeks around Hallowe’en.