Abstract: An electrical control system for a fuel circuit including a low pressure pump, a high pressure pump, a throttle valve and a pressurizing valve connected in series between a fuel reservoir and the fuel injectors of a gas turbine engine includes a first device including a first solenoid controlled valve capable of interruption of the connection between the outlet of the throttle valve and an inlet to a pressure drop detector which is normally connected across the throttle valve. The output of the pressure drop detector controls a control valve which can by-pass high pressure fuel output from the high pressure pump back to the pump inlet. The first device includes two, identical, parallel control channels each provided with its own independent power supply, a control first switch with two positions each leading to a respective processing circuit which has its output connected to one terminal of a respective solenoid winding of the bistable first solenoid controlled valve.