Preheat oven to 180 degrees C. Grease baking trays.
Mix together flour, baking powder, bicarb soda and salt. Stir 1/2 cup orange juice and 1 teaspoon zest into the flour mixture.
Cream copha and white sugar together. Mix egg into the sugar mixture thoroughly. Slowly blend flour mixture into the egg and sugar mixture. Drop by teaspoonful onto greased baking tray.
Bake for 8 to 10 minutes.
Make the icing: Mix icing sugar and 2 tablespoons butter together until smooth. Pour 2 tablespoons orange juice and 1 teaspoon orange zest into the sugar and butter mixture, mix well. When the biscuits have cooled spread the icing generously over the tops of the biscuits.