A method of charging a vehicle (170) having a battery is disclosed. The method comprises the step of stopping power supply to a connector (160) in response to an interruption in the power supplied to the battery via said connector (160), wherein said interruption occurs while said connector (160) is connected to a power supply means such as a charging station (100). Also disclosed is a method comprising the steps of detecting an interruption in an authorised power supply and requiring successful completion of a reauthorisation step prior to any further power being supplied to the vehicle. Both methods prevent the theft of a power supply by an unauthorised user. Also disclosed are systems comprising means for implementing the various methods.
