Aspects of this invention relate to a barrier for fixing to an portion of a wall. The barrier includes at least one plate that is securable to the wall. For each plate, there is a vertical upright attached to and extending upwardly from the plate to which the barrier is secured. The barrier is held by the vertical upright above the upper portion of the wall as required. removable from the vertical upright to allow access to the upper portion of the wall as required. In one aspect, at least a portion of the barrier is moveable relative to a remainder of the barrier and between a first portion, where it is located above an upper edge of the wall, and a second portion, where access is then provided to the upper wall edge above which the movable barrier portion was positioned.