The present invention relates to current measurement apparatus 100. The current measurement apparatus 100 comprises a measurement arrangement 110, 114 which is configured to be disposed in relation to a load 108 which draws a current signal, the measurement arrangement being operative when so disposed to measure the load drawn current signal. The current measurement apparatus 100 also comprises a signal source 112 which is operative to apply a reference input signal to the measurement arrangement 110, 114 whereby an output signal from the measurement arrangement comprises a load output signal corresponding to the load drawn current signal and a reference output signal corresponding to the reference input signal. The current measurement apparatus 100 further comprises processing apparatus 116 which is operative to receive the output signal and to make a determination in dependence on the reference output signal and the load output signal, the determination being in respect of at least one of the load drawn current signal and electrical power consumed by the load.