Cream margarine until soft and add sugar and beat until light and fluffy.
Add the eggs one at a time, beting well between each addition.
Mix in marmalade, sultanas and flour.
Turn into greased and bottom-lined deep 7 inch cake tin.
Level the surface, and bake at 350℉ (180℃) for 1 to 1½ hours or until a skewer comes out clean.
Cool for 15 minutes and turn out onto rack to cool completely.