Just to shove my oar in for a moment... British food and drink outlets seem to go loopy every St Patrick's Day, and I must concur with Rosie and Breadmaster's opinion that it's the US influence that fuels this. On the other side of the coin, I went into my local Tesco outlet (and it's the major one for the area) at the end of February to see what I could get to celebrate St David's Day (what with having Welsh ancestry). I was laughed at by staff. When I suggested that, surely, the massive efforts poured into their St Patrick's Day marketing might indicate a degree of 'racial bias' (I stopped short of institutional racism!), I was told "Well, you can buy a daffodil or a leek." I would have replied, but the manager had lost interest and walked away.
Well, there is always plenty of stuff available in Wales to celebrate it, but then Welsh cakes, although nice, aren't as exciting as Guiness, for most people. I think although it's definitely commercial - no-one really minds an excuse to drink and eat, just like at Christmas and Easter.
Right. My ambition now is to plan the mass-marketing off the back of St. David's Day. St. George's Day needs no help, in Clinton's at least, and I suspect is fuelled quite nicely by the football industry.