A working machine having a movable implement, a hydraulic actuator (32, 16) for displacing the implement, and a hydraulic control system to enable an operator to control movement of the implement, the control system comprising: a supply line for supplying hydraulic fluid at a high pressure, a supply line for supplying hydraulic fluid at a pilot pressure lower than the high pressure, a hydraulic return line, a pilot-operated valve (100, 200) for selectively connecting the high pressure supply line and the return line to the hydraulic actuator (32,16) to displace the implement, the valve (100, 200) having a spool movable by the action of the hydraulic pilot pressure, a manually operable joystick, a hydraulic pilot valve (110,210) for regulating the supply of hydraulic pilot pressure to the pilot-operated valve in dependence on the position of the joystick, an electrically operated valve (130, 230) for bypassing the pilot valve (110,210) and supplying hydraulic pilot pressure to the pilot-operated valve (100, 200) independently of the position of the joystick, and an electrical circuit (140,240) that includes a manually operable switch (144,244) and that is triggered by operation of the switch (144,244) to initiate a return of the implement to a predetermined state by actuation of the electrically operated valve (100,200), independently of the operation of the joystick, characterized in that a hydraulic pressure sensor (146,246) is connected to a line (120,220) leading from the hydraulic pilot valve (110,210) to the pilot-operated valve (100,200), and the electrical circuit (140,240) is only triggered by operation of the manually operable switch (144,244) when the pressure sensed by the sensor (146,246) exceeds a predetermined value. a supply line for supplying hydraulic fluid at a high pressure, a supply line for supplying hydraulic fluid at a pilot pressure lower than the high pressure, a hydraulic return line, a pilot-operated valve (100, 200) for selectively connecting the high pressure supply line and the return line to the hydraulic actuator (32,16) to displace the implement, the valve (100, 200) having a spool movable by the action of the hydraulic pilot pressure, a manually operable joystick, a hydraulic pilot valve (110,210) for regulating the supply of hydraulic pilot pressure to the pilot-operated valve in dependence on the position of the joystick, an electrically operated valve (130, 230) for bypassing the pilot valve (110,210) and supplying hydraulic pilot pressure to the pilot-operated valve (100, 200) independently of the position of the joystick, and an electrical circuit (140,240) that includes a manually operable switch (144,244) and that is triggered by operation of the switch (144,244) to initiate a return of the implement to a predetermined state by actuation of the electrically operated valve (100,200), independently of the operation of the joystick, characterized in that a hydraulic pressure sensor (146,246) is connected to a line (120,220) leading from the hydraulic pilot valve (110,210) to the pilot-operated valve (100,200), and the electrical circuit (140,240) is only triggered by operation of the manually operable switch (144,244) when the pressure sensed by the sensor (146,246) exceeds a predetermined value.