An LED lamp suitable for use in a luminaire, the LED lamp adapted for receiving electrical power from the luminaire and comprising: one or more LEDs; a ballast protection circuit including an impedance; a filter circuit; a switched-mode power supply for driving the LEDs; one or more sensing circuits for generating at least one output, in dependence on whether the electrical power received from the luminaire indicates that the electrical power is generated via a magnetic ballast, an electronic ballast which operates as a constant current ballast, an electronic ballast which operates as a constant power ballast, or not via a ballast; and a plurality of switches for defining a plurality of operation modes of the LED lamp, and for switching among the plurality of operation modes in dependence on the at least one output of the sensing circuits.