A support device with at least first and second support members movable with respect to each other in a direction parallel to their longitudinal axes. The support device having distal ends and the distal ends each including an anchor portion to engage directly or indirectly with a suitable surface in use, the support device including a biasing assembly for biasing one or more of the distal ends of the support device into engagement with a suitable surface in use, and the biasing assembly is located at or adjacent an end of at least one of said first and second support members and between said support member end and the anchor portion nearest to said support member end. The support device is particularly suited to a safety fence or assembly or a worker protection system.