Abstract: An actuator for a flow control valve comprises an electric motor (112) for driving an output shaft connected to the valve; an electric power supply (128) having a characteristic feature for defining an intended direction of drive of the electric motor; a sensor (132) for detecting the characteristic feature; a connector (134) for connecting the electric current supply to the electric motor; and a control system (130) arranged to connect the electric power supply to the electric motor. Operation of the actuator comprises providing electric current; detecting the characteristic feature; determining the intended direction of drive of the electric motor from an output of the sensor indicative of the characteristic feature of the electric current; determining that there are no predetermined conditions inhibiting operation of the electric motor in the intended direction of drive of the electric motor; and operating the connector to connect the electric power supply to the electric motor.