A method for controlling and damping the motion of a hydraulic actuator in an electro hydrostatic actuator system comprising an electric motor, a hydraulic pump and a hydraulic fluid circuit connecting the hydraulic pump and the hydraulic actuator, the method comprising: energising the electric motor to drive the hydraulic pump to supply hydraulic fluid to the hydraulic actuator through the hydraulic fluid circuit in an active mode of operation; providing a flow path between the hydraulic actuator and the hydraulic pump in a damping mode of operation, in the case of a system failure, such that hydraulic fluid can flow through the hydraulic pump when the hydraulic actuator is driven by an external force; the electric motor effectively acting as a generator when it is driven by the hydraulic pump; determining a desired amount of damping to be applied to the hydraulic actuator in the damping mode of operation; wherein determining the desired amount of damping comprises determining the force which is applied to the hydraulic actuator by measuring the electrical energy generated by the electric motor which comprises using electronic control circuitry arranged to measure the electrical energy generated, wherein providing the electronic control circuitry comprises arranging components of the electronic control circuitry so as to be powered by the electrical energy generated by the electric motor; and subsequently providing the electric motor with one or more energy consuming means configured to provide the desired amount of damping, such that in the damping mode of operation when the hydraulic actuator is driven by an external force, the hydraulic fluid flowing via the flow path through the hydraulic pump causes the hydraulic pump to drive the electrical motor so as to generate energy which is consumed by the energy consuming means. energising the electric motor to drive the hydraulic pump to supply hydraulic fluid to the hydraulic actuator through the hydraulic fluid circuit in an active mode of operation; providing a flow path between the hydraulic actuator and the hydraulic pump in a damping mode of operation, in the case of a system failure, such that hydraulic fluid can flow through the hydraulic pump when the hydraulic actuator is driven by an external force; the electric motor effectively acting as a generator when it is driven by the hydraulic pump; determining a desired amount of damping to be applied to the hydraulic actuator in the damping mode of operation; wherein determining the desired amount of damping comprises determining the force which is applied to the hydraulic actuator by measuring the electrical energy generated by the electric motor which comprises using electronic control circuitry arranged to measure the electrical energy generated, wherein providing the electronic control circuitry comprises arranging components of the electronic control circuitry so as to be powered by the electrical energy generated by the electric motor; and subsequently providing the electric motor with one or more energy consuming means configured to provide the desired amount of damping, such that in the damping mode of operation when the hydraulic actuator is driven by an external force, the hydraulic fluid flowing via the flow path through the hydraulic pump causes the hydraulic pump to drive the electrical motor so as to generate energy which is consumed by the energy consuming means.