A system for displaying a banner (70) on a vehicle comprises mounting means (160) having channels (163), retaining means (112) for retaining the banner and associated with first and second locking members (124, 140) for engagement with the channels, the first locking member having a strut (134) locatable in a first channel, the second locking member having a second protruding strut (148) locatable in the same channel, and the first locking member further having a third protruding strut (135) spaced apart from the first strut and locatable within a second channel. When the locking members (124, 140) are aligned, the first strut (134) and second strut (148) are adjacent each other, the adjacent sides being parallel and the struts are located in the channels for secure attachment to the mounting means. The retaining means (112) may be connectable to the first locking member (124), e.g. by a pivot (115, 117), or it may form an integral member (53, 54, 35) therewith.