Preheat the oven to 200 degrees C. Line a 12-hole muffin tray with muffin cases.
In a large mixing bowl tip the flour, sugar and oat bran; form a well in the centre.
In another bowl using a fork or potato masher mash the bananas then mix in the eggs, oil and milk.
Pour the banana mixture into the dry ingredients. Using a wooden spoon stir everything together for a few seconds until only just combined but still quite lumpy. The lumps will disappear during baking.
Spoon the mixture into the muffin cases and bake for 15-20 minutes or until golden brown.
Let the muffins cool for 2 minutes in the tin then transfer to the wire rack to cool.
For the icing: Add enough orange juice to the icing to make a smooth paste. Drizzle the orange icing over the muffins and leave to set before serving.