The present application relates to a control system (49) for controlling a motor vehicle suspension (3). The suspension (3) has a plurality of adjustable height suspension units (19, 21, 23, 25) and a suspension control means (53) is provided to control the suspension units (19, 21, 23, 25). The control system (49) has a receiver for receiving height data form height sensors (41, 43, 45, 47) to provide height measurements for each suspension unit (19, 21, 23, 25). A suspension modelling means is provided for modelling the height of each suspension unit (19, 21, 23, 25). The control system (49) is configured to detect an unrequested suspension height change when the difference between the modelled height and the measured height of one or more suspension units (19, 21, 23, 25) exceeds a threshold. The present application also relates to a motor vehicle; and a method of detecting an unrequested suspension height change.