In a large saucepan cover the potatoes, garlic and bay leaves with the milk and water and set over a high heat.Bring to the boil and reduce the heat to a gentle simmer.
Cook for about 15 minutes or until the potatoes are soft.Drain in a colander and reserve 200 ml of the cooking liquid but discard the bay leaves.
Mash the potatoes and garlic and add cooking liquid until it is the consistency that you like. Stir in the olive oil and season with salt and pepper.