A two-wire lighting system comprising a lighting device connected to a first wire, and a light switch connected to a second wire, and a connecting wire connecting the light switch to the lighting device. The first and second wires are connected across a mains system. The lighting device comprises a lighting controller and a bleeder controllable by the lighting controller. The light switch comprises a wireless transmitter, a switch controller and a mechanical switch connected to the switch controller. The switch controller is configured, in response to actuation of the mechanical switch by a user, to generate a bleeder activation signal in the connecting wire. The lighting controller is configured to activate the bleeder according to the bleeder activation signal so as to induce an operational current in the wires. The switch controller is configured to use the operational current to transmit a message from the wireless transmitter.