Do they celebrate Saint Patrick's Day in the United Kingdom? I know they do in Canada (which is very much part of the British Commonwealth of Nations). Plus you know the Cross of Saint Patrick (red X on a white field) is still part of the British Union Jack. I think it represents Northern Ireland. But still. And while we're at it, what do they do on the day, if anything? Do they just ignore it? And what did they do when Ireland was still part of the United Kingdom?
St. Pats day is usually celebrated with lots of booze and dancing and generally partying. (Any excuse) An Irish Celebration, though with; as with all historical lore, has deeper undertones. https://www.themarysue.com/the-truth-about-saint-patrick-snakes-pagans-and-more/ The Letter to Coroticus implies that the Franks were still pagans at the time of writing: their conversion to Christianity is dated to the period 496–508 In the work St. Patrick seeks to convert the warriors to Christianity, while they defend their pagan past. The heroic pagan lifestyle of the warriors, of fighting and feasting and living close to nature, is contrasted with the more peaceful, but unheroic and non-sensual life offered by Christianity The Patrick portrayed by Tírechán and Muirchu is a martial figure, who contests with druids, overthrows pagan idols, and curses kings and kingdoms