Sitting on a British Airways flight heading to NYC, tucking into a full-English which was tolerable but not great, I had a tap on the arm from the Japanese businessmen sitting on the same aisle, "excuse me -- what is this?" he asked pointing to the black pudding on his plate, "that's black pudding, a type of blood sausage" I replied, at which point he thanked me, turned a little pale and pushed the slices to the side of the plate.