A responsive load system for delivering a responsive load service to an electricity power supply network having a nominal operating value ( f nominal) for a variable physical parameter ( f) of the electricity supply network, the responsive load system comprising: a remote controller and at least one load controller adapted to control electricity consumption of one or more associated electrical loads in the vicinity of the load controller, the responsive load system being characterized by each load controller including: a parameter measuring device for regular measurement of the variable physical parameter ( f) of the electricity supply network, a power consumption controller for determining and for causing adjustment of the power consumption of at least one of the one or more associated electrical loads to deliver a responsive load service in response to a detected difference between a recent measurement of the transitory variable physical parameter ( f) of the electricity supply network and the nominal operating value ( f nominal) of the physical parameter, and a first communication device adapted for receiving command signals from the remote controller, each command signal being representative of an adjustment to the amount of responsive load service being delivered by the one or more associated electrical loads, the remote controller including: a parameter measuring device for regular measurement of the variable physical parameter ( f) of the electricity power supply network, an analyser adapted to determine adjustments to the responsive load service delivered by the one or more electrical loads of the at least one load controller; and a second communication device for transmitting to the at least one load controller a command signal representative of a determined responsive load service correction, wherein each load controller is adapted to receive the command signal and apply the responsive load service correction as an offset to power consumption adjustments determined by the power consumption controller. a parameter measuring device for regular measurement of the variable physical parameter ( f) of the electricity supply network, a power consumption controller for determining and for causing adjustment of the power consumption of at least one of the one or more associated electrical loads to deliver a responsive load service in response to a detected difference between a recent measurement of the transitory variable physical parameter ( f) of the electricity supply network and the nominal operating value ( f nominal) of the physical parameter, and a first communication device adapted for receiving command signals from the remote controller, each command signal being representative of an adjustment to the amount of responsive load service being delivered by the one or more associated electrical loads, a parameter measuring device for regular measurement of the variable physical parameter ( f) of the electricity power supply network, an analyser adapted to determine adjustments to the responsive load service delivered by the one or more electrical loads of the at least one load controller; and a second communication device for transmitting to the at least one load controller a command signal representative of a determined responsive load service correction,