Preheat the oven to 160C/325F/gas mark 3
Use a 900g/2 lb loaf tin.
Grease the loaf tin. Line the base with greaseproof paper. Grease the paper. Cream the butter, rind and sugar in small bowl until light and fluffy. Add the sour cream and mix until well combined. Transfer the mixture to large bowl, stir in sultanas and grated carrot, then the sifted dry ingredients and orange juice. Spread into the prepared tin. Bake for 1 1/2 hours. Stand for five minutes before turning on to wire rack to cool. Top with icing when cake is cold.
Orange Icing: Beat butter in small bowl until light and fluffy, gradually beat In sifted icing sugar, then juice and a little colouring; beat until smooth.
