Preheat oven to 190 degrees C. Grease and line a 900g loaf tin with baking paper.
In a mixing bowl combine the flour, baking powder and salt. Mix together and set aside.
In a separate bowl, cream the butter and sugar until light and fluffy. Add the eggs one at a time, beating well after each addition. Gradually mix in the lemon juice followed by the flour mixture, alternating with the milk until the mixture is thick and smooth. Fold in the lemon zest and mango. Spoon into the prepared loaf tin and smooth the top.
Bake in the preheated oven for 60 to 70 minutes, or until a skewer inserted into the centre of the cake comes out clean. Remove from the oven and allow to cool before slicing.
Avoid opening the oven door in the first 50 minutes of cooking as this will help to prevent the cake sinking in the middle.