Abstract: A number of resistive elements are incorporated into the aerofoil in the vicinity of its leading edge. Each of the resistive elements is electrically connected to the other resistive elements at its distal end and is fitted at its proximal end with means of connection to an electrical power supply. The resistive elements are split between a first set that includes at least two resistive elements and a second set that includes at least one resistive element. In service, the resistive of the first set are powered in turn, while each resistive element of the second set acts as a return path for the electricity and is powered continuously or almost continuously.