A lighting control device, comprising a housing including: a primary input power connection for receiving power from a primary power supply network; a secondary input power connection for receiving power from a secondary power supply; an output power connection (49, 51) for delivering power to one or more light sources; and electronic circuitry for controlling delivery of power from the primary and secondary input power connections to the output power connectionso as to control delivery of power to the one or more light sources; wherein the electronic circuitry comprises: means for determining an indication of an external electrical loading on the primary power supply network coupled, in use, with the primary input power connection; and means (31, 35) for varying the power drawn from the primary and secondary input power connections in dependence upon the determined indication of the external electrical loading on the primary power supply network; characterised in that the lighting control device has a normal mode of operation in which the electronic circuitry is arranged to deliver power from the primary input power connection to the output power connection (49, 51) so as to deliver power to the one or more light sources; an economy mode of operation in which the electronic circuitry is arranged to take no or minimal power from the primary input power connection and to deliver power from the secondary input power connection to the output power connection (49, 51) so as to deliver power to the one or more light sources; and a charging mode of operation in which the electronic circuitry is arranged to deliver power from the primary input power connection to the secondary input power connection so as to charge the secondary power supply; in that the determining means is arranged to determine a measurement of the frequency of a power signal received at said primary input power connection; in that the electronic circuitry is arranged to use the frequency measurement to determine if there is a high loading, a low loading or a normal loading on the primary power supply network; and in that the electronic circuitry is arranged to configure the control device to operate in the charging mode if there is a low loading on the primary power supply network; to operate in the normal mode if there is a normal loading on the primary power supply network; and to operate in the economy mode if there is a high loading on the primary power supply network. a primary input power connection for receiving power from a primary power supply network; a secondary input power connection for receiving power from a secondary power supply; an output power connection (49, 51) for delivering power to one or more light sources; and electronic circuitry for controlling delivery of power from the primary and secondary input power connections to the output power connectionso as to control delivery of power to the one or more light sources; wherein the electronic circuitry comprises: means for determining an indication of an external electrical loading on the primary power supply network coupled, in use, with the primary input power connection; and means (31, 35) for varying the power drawn from the primary and secondary input power connections in dependence upon the determined indication of the external electrical loading on the primary power supply network; means for determining an indication of an external electrical loading on the primary power supply network coupled, in use, with the primary input power connection; and means (31, 35) for varying the power drawn from the primary and secondary input power connections in dependence upon the determined indication of the external electrical loading on the primary power supply network; characterised in that the lighting control device has a normal mode of operation in which the electronic circuitry is arranged to deliver power from the primary input power connection to the output power connection (49, 51) so as to deliver power to the one or more light sources; an economy mode of operation in which the electronic circuitry is arranged to take no or minimal power from the primary input power connection and to deliver power from the secondary input power connection to the output power connection (49, 51) so as to deliver power to the one or more light sources; and a charging mode of operation in which the electronic circuitry is arranged to deliver power from the primary input power connection to the secondary input power connection so as to charge the secondary power supply; in that the determining means is arranged to determine a measurement of the frequency of a power signal received at said primary input power connection; in that the electronic circuitry is arranged to use the frequency measurement to determine if there is a high loading, a low loading or a normal loading on the primary power supply network; and in that the electronic circuitry is arranged to configure the control device to operate in the charging mode if there is a low loading on the primary power supply network; to operate in the normal mode if there is a normal loading on the primary power supply network; and to operate in the economy mode if there is a high loading on the primary power supply network.