An electronic security apparatus for a vehicle being capable of controlling the performance of a vehicle function in response to a user attempting to start the engine of the vehicle. The system being capable of controlling the performance of the vehicle function in response to being provided with a first security code from an electronic key (12). The security system has a secured mode of operation in which the system may be set to a limited authorization state in which performance of the vehicle function is enabled. The system also has an unsecured mode of operation in which the user performing the action enables performance of the vehicle function irrespective of whether or not one or more conditions are met.