Preheat your oven to 350°F (175°C). Grease a loaf pan.
In a mixing bowl, combine flour, sugar, baking powder, and salt.
In another bowl, cream the butter and then add the eggs one at a time, beating well after each addition.
Stir in the milk and lemon zest into the butter mixture.
Gradually add the dry ingredients to the wet ingredients, mixing just until combined.
Gently fold in the blueberries.
Pour the batter into the prepared loaf pan and bake for 60 minutes or until a toothpick inserted into the center comes out clean.
Let the bread cool in the pan for 10 minutes, then transfer to a wire rack to cool completely.