Abstract: A vehicle suspension system has an anti-roll portion bar arrangement comprising a torsion bar extending transversely of the vehicle, and first and second arms extending transversely from the torsion bar, one arm being connected to the torsion bar by a rotary actuator for moving the arm angularly about the torsion bar. The torsion bar is supported for angular movement about its torsional axis by a support member, for example, a tubular housing which is mounted to the vehicle structure by brackets which preferably extend lengthwise of the vehicle, forwardly or rearwardly, from the support member to be pivotally connected to the vehicle structure. As well as providing packaging benefits, the arrangement has the effect that the support member stores some energy in the system, lessening the demands on the properties of the torsion bar.