In a large bowl thoroughly combine flour, sugar, prunes, walnuts, baking powder, orange peel, salt, and baking soda. Stir in orange juice, oil and, eggs just until mixed. Turn into greased 9x5x3-inch loaf pan.
Bake in preheated 350-degree oven for 45 minutes or until pick inserted in center comes out clean. Cool in pan 5 minutes, then invert on rack and cool completely, or serve warm with butter or marmalade.