Soak the mixed fruit and glace cherries in the hot black tea for 2 hours.
Preheat the oven to 190 C / Gas 5. Grease and line a 900g loaf tin with baking parchment.
Put the packet of Mrs Crimbles® cake mix in a small bowl, mix in the spice. Add the egg, cold water, melted margarine and treacle. Whisk until smooth, about 1 minute. Add the fruit and tea and mix well. Pour the mixture into the prepared tin.
Bake in the preheated oven for 45 minutes until a skewer inserted into the centre comes out clean. Remove from the oven and cool before serving.