Sift the flour, baking powder and salt into a bowl and mix together.
In a separate bowl, add the lemon juice yo the sugar and mix until the sugar is moist and aromatic. Add the lemon juice, water, eggs and oil and mix well.
Add the flour mixture to the lemon batter and mix well until it forms a smooth batter with no lumps.
Pour into a loaf tray to ¾ of its height. Bake for about 30 minutes, until a toothpick inserted into the centre comes out clean.
Meanwhile, make the lemon icing: add three tablespoons of the lemon juice to the icing sugar and mix well. Add the remainder as necessary a few drops at a time until it forms a runny, but not too runny, icing.