An English delicacy. A large Sausage made from large lumps of pork fat suspended in congealed blood and cereal (usually oats), and served sliced and fried (or grilled), usually at breakfast. Never seen as a 'healthy eating' option but still served occasionally by today's health aware Army chefs, it is an acquired taste and not for vegetarians.
Blood sausages are quite common and popular in Europe. For example, the French eat 'Boudins Noir' and the Germans like a nice 'Blutwurst', but Black Pudding is undoubtedly the Real Man's version.