Combine the flour, dry mustard, paprika and baking powder in a medium bowl. Beat the butter, either by hand or with an electric mixer at medium speed, until light and fluffy. Slowly beat in the cheddar cheese and Worcestershire sauce. Gradually add the flour mixture, stirring with a fork, until well blended. On a lightly floured surface, shape the dough into a long roll about 4 cm in diameter. Wrap in plastic wrap or foil. Place on a platter and refrigerate for at least 2 hours, better overnight. Preheat the oven to 160ºC . Slice the dough about 1 cm thick. With your hands, roll each slice into a ball. Flatten slightly and place on an ungreased baking sheet about 5 cm apart. Bake 8 minutes in the preheated oven. Biscuits will only brown slightly on the bottom. ----------------------------------------------------------------------------