A color temperature tunable white light source comprises a first LED arrangement comprising at least one blue emitting LED configured to excite a remote phosphor and a second LED arrangement comprising at least one red emitting LED. The LED arrangements are configured such that the composite light emitted by the LED arrangements appears white in color. The relative drive currents of the LEDs is controllable, and thus variable in relative magnitude, such that the color temperature of the composite light emitted by the source is electrically tunable.