Remove the stalks, wash the damsons and put into the pan with the water. Stew slowly until the damsons are well broken’ down. Add the sugar, stir over a low heat till dissolved, bring to the boil, then boil rapidly. Remove stones as they rise to the surface (a stone-basket clipped to the side of the pan is useful for holding the stones, and allows any liquid to drip back into the pan). Continue boiling rapidly until setting point is reached. (Test for set after about 10 min. boiling.) Skim, pour into dry, warm jars and cover.