An actuator comprising a first part and a second part, the first part being configured to move relative to the second part, wherein a labyrinth seal is provided between the first part and the second part, the labyrinth seal being configured to restrict the flow of gas from a first side of the labyrinth seal to a second side of the labyrinth seal, wherein one or more inlets and one or more outlets are provided within the labyrinth seal, the one or more inlets being configured to provide gas to a location within the labyrinth seal and the one or more outlets being configured to remove at least part of the gas from a location within the labyrinth seal.