A controller for controlling a vehicle, the vehicle comprising a detection means having a detection zone and a lateral non-detection region, the controller comprising: an input for receiving an object detection signal from the detection means; a processor arranged to generate a control signal for controlling a vehicle system in dependence on the received object detection signal; an output for outputting the control signal wherein the processor is arranged to generate a vehicle speed control signal to vary a vehicle speed about a current vehicle speed in order to bring an object within the lateral non-detection region into the detection zone of the detection means; and the output is arranged to output the vehicle speed control signal.