The present invention relates to a control system for a hybrid electric vehicle having an engine (121) and first (123C) and second (123B) electric machines operable as propulsion motors. The second electric machine is arranged to be drivably coupled to the engine, the engine being arranged to be drivably coupled to a driveline of the vehicle by clutch means (122). The system is operable to control the vehicle to operate in one selected from amongst: an engine-driven mode in which the clutch means is closed and the engine applies torque to the driveline of the vehicle; an electric vehicle (EV) mode in which the clutch means is open and the first electric machine applies torque to the driveline; and an EV boost mode in which the clutch means is closed and both the first and second electric machines apply torque to the driveline, the engine being motored by the second electric machine, the mode in which the vehicle is operated being selected by the system in dependence on the value of one or more vehicle parameters.