Preheat the oven to 150C/300F/gas mark 2
Use a 900g/2 lb loaf tin.
Combine dates, tea and soda in bowl; cover, stand overnight. Line the base and sides of the loaf tin with greaseproof paper. Grease the paper well.
Cream the butter and sugar in small bowl until light and fluffy, add sour cream and mix well. Transfer to large bowl. Stir in walnuts, sifted flour and grape juice then date mixture. Pour into prepared tin. Bake for about 1 hour. Stand 5 minutes before turning on to wire rack to cool.
