Today is Yorkshire Day, due to be celebrated with flat cap-flinging, a hog roast, much singing of Ilkley Moor Bah’t Hat, brass bands at full blast, tides of doggerel, and sundry proclamations. These are no arcane ceremonies, like the Planting of the Penny Hedge in Whitby’s upper harbour on Ascension Eve, for which no entirely convincing explanation has been forthcoming.