Preheat oven to 400 degrees F. Combine the flour, sugar, salt, baking powder and baking soda in a large bowl. Add butter and mix with your fingertips to a coarse meal. Add buttermilk and mix just until combined. Add currants, if desired.

Transfer dough to a floured board and divide into 2 parts. Roll each to 3/4 inch thick rounds. Cut each round into 8 wedges and place slightly separated on a greased baking sheet. Brush the tops with the cream, and bake for 15 minutes, or until lightly browned. Serve warm, split in half with butter and marmalade.