Here's the recipe for Christmas pudding from Food Facts for the Kitchen Front. I can't say that it sounds particularly appetising!
War and Peace Christmas Pudding
Mix together 1 cupful of flour, 1 cupful of breadcrumbs, half a cupful of suet, half a cupful of mixed dried fruit, and, if you like, a teaspoonful of mixed sweet spice. Then add a cupful of grated raw potato, a cupful of grated carrot, and finally a level teaspoonful of bicarbonate of soda dissolved in two tablespoonfuls of hot water. Mix all together, turn into a well-greased pudding bowl. The bowl should be not more than two-thirds full. Boil or steam for at least 2 hours.