A color tunable light source comprises: a first light emitting diode (LED) arrangement operable to emit light of a first color and a second LED arrangement operable to emit light of a second color, the combined light output comprising the output of the source. One or both LED arrangements comprises a phosphor provided remote to an associated LED operable to generate excitation energy of a selected wavelength range and to irradiate the phosphor such that it emits light of a different color wherein light emitted by the LED arrangement comprises the combined light from the LED and phosphor and control means operable to control the color by controlling the relative light outputs of the two LED arrangements. The color can be controlled by controlling the relative magnitude of the drive currents of the LEDs or by controlling a duty cycle of PWM drive current.