1. A vehicle control system, comprising: a supervisor module, and a plurality of controller modules responsive to commands from the supervisor module, in which the supervisor module includes a control constraint set and is arranged to receive control demands from each of the controller modules and accede to the demands within the limits of the constraint set, the supervisor module achieving full integration with the controller modules by taking into account said control demands before sending control commands to controller modules, said control demands comprising local condition information, and said control commands comprising appropriate set points for said controller modules, such that desired vehicle output parameters are achieved.